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Discussion Starter #1
Hello all,
I’m having problems sifting through the thousands of posts here and elsewhere on the interweb. Can anybody steer me in the right direction here to build a 400 h.p.ish, pump gas 400?
I’ve got a 67’ GTO w/numbers matching engine I’m parking under my shop bench to preserve. To replace it I’ve found a 67’ Grand Prix 400, 350 h.p. and 670 heads. I hope to pick the engine up this weekend, break it down and make the salvageability/machining assessment by next week. If everything is reusable (and with hoping to keep the 670 heads for year correctness ) is 400 hp a reality on pump gas without having to go the stroker route? If so what recipe will get it done? Cam, pistons, head work, quench, etc.?
I have seen some great posts from Bear, Pontiac Jim and others on different engine combinations, but I haven’t been able to find much on this one (or maybe I missed it?)
Any help is much appreciated!
 

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400hp is no problem at all with a 9:1 CR stroker.

Not too hard to make 400hp with a high CR 400. But you'll need to mix in racing gas or octane booster.

But, when you back the CR off to 9.5 or less, it becomes a bit more difficult.

A Voodoo cam can make up for much of the CR loss. They are said to increase cyl pressure, by closing the intake valves sooner. I'm sure Paul Carter has built lots of pump gas 400's that made 400hp & more. He loves the Voodoo cams.

For an extra $1000-$1500, you can have a hyd roller cam set-up. The correct HR will make more power than most HFT cams.

With the 670 heads, dish pistons will be needed, to get the CR down to 9.5. But, most every time I say that on a Pontiac forum, some guy will come on & say how he has been running over 10:1 CR with pump gas, for years, with absolutely no problems at all. Some also say you don't need hardened valve seats, in the early heads. Others say they're a good idea for the exhaust valve seats, for use with unleaded gas.

I'd rather err on the safe side. No reason to take a chance IMO.

Icon IC891-030 pistons have a 14cc dish.

https://www.cnc-motorsports.com/icon-ic891-030-forged-dish-pistons-4150-bore.html

I'd recommend RPM H-beam rods. They're $400 shipped. You can actually get by with good quality properly resized cast rods, using ARP bolts. But forged rods are better.

SAE 4340 STEEL H-BEAM

Butler sells some of the new Eagle 5140 forged rods for $349 + shipping. But they are heavier & not as strong as H-beams.

https://butlerperformance.com/i-31643273-eagle-5140-forged-i-beam-rod-6-625-2-250-pontiac-rj.html?ref=category:1234812

Best to go with one-piece stainless valves, such as the Ferrea 5000 series. A good head job also includes bronze valve guides, good seals, 7/16 studs, etc. Best to have 'em done by somebody who has lots of experience doing performance Pontiac heads. Porting is not needed, for 400hp. A gasket match on the ports is a good idea tho. But, there have been plenty of 400hp Pontiac engines with completely original untouched ports.

You mentioned quench. Most agree that .040 or slightly less is a good quench distance.

A good correctly built & tuned Q-jet, & a stock iron intake are plenty good to 400hp & well beyond.

I'm sure some of these other guys can give you more details than this.

Good luck with it !
 

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Discussion Starter #3 (Edited)
Thanks for the reply bigD!
I really appreciate the recommendations.
I plan on having the parts and pieces down to the machine shop next week barring any major findings in the tear down. If everything is a go I’m planning on the following beside the normal clean and inspection.

1.Line bore, block the deck. I’ll shoot for that recommended quench.

2.Hone to 30 over for ease of finding new pistons. Dished pistons for decreased C/R. I will go with the upgraded rods ARP bolts throughout. (thanks for the rod recommendation!) Balance connecting rods and pistons. Do you have any ring recommendations?

3.Heads reconditioned w/hardened seats, SS valves, upgraded bronze guides/springs. You don’t recommend porting the heads?

4.Polish/balance/chamfer the crank (hopefully it won’t need too much, it’s from a low mileage family car). Do you have any bearing preferences throughout the engine ?

5. I’ll check into the Voodoo cam, thanks for that! If I go with a roller setup is there any concerns on this engine with bracing? (Sorry I’m still learning on these Pontiac’s)

6. Rear seal (a small but big deal) I’m planning on the rope style seal from Best Gasket. Pros/Cons vs. Vitron?

7. I was told there is a hidden oil galley plug on the rear of the engine that not only “must be there” but was recommended to drill and tap it for better cam oiling. Good or Bad idea?

8. Is an upgraded oil pump available /required for this build?

9. Recommendations for timing chains?

10. I’d like to keep the original intake manifold, Q-jet w/forward fuel line and ignition for originality.

I really appreciate all the insight here. We don’t have (or I haven’t found) much of a Pontiac following here in Salt Lake. So I don’t have many people to bounce ideas off of. I’ve found what I feel is a very capable machine shop (tooling wise), but unfortunately this and other shops I’ve talked to local seem to have limited Pontiac experience.
 

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Thanks for the reply bigD!
I really appreciate the recommendations.
I plan on having the parts and pieces down to the machine shop next week barring any major findings in the tear down. If everything is a go I’m planning on the following beside the normal clean and inspection.

1.Line bore, block the deck. I’ll shoot for that recommended quench.

2.Hone to 30 over for ease of finding new pistons. Dished pistons for decreased C/R. I will go with the upgraded rods ARP bolts throughout. (thanks for the rod recommendation!) Balance connecting rods and pistons. Do you have any ring recommendations?

3.Heads reconditioned w/hardened seats, SS valves, upgraded bronze guides/springs. You don’t recommend porting the heads?

4.Polish/balance/chamfer the crank (hopefully it won’t need too much, it’s from a low mileage family car). Do you have any bearing preferences throughout the engine ?

5. I’ll check into the Voodoo cam, thanks for that! If I go with a roller setup is there any concerns on this engine with bracing? (Sorry I’m still learning on these Pontiac’s)

6. Rear seal (a small but big deal) I’m planning on the rope style seal from Best Gasket. Pros/Cons vs. Vitron?

7. I was told there is a hidden oil galley plug on the rear of the engine that not only “must be there” but was recommended to drill and tap it for better cam oiling. Good or Bad idea?

8. Is an upgraded oil pump available /required for this build?

9. Recommendations for timing chains?

10. I’d like to keep the original intake manifold, Q-jet w/forward fuel line and ignition for originality.

I really appreciate all the insight here. We don’t have (or I haven’t found) much of a Pontiac following here in Salt Lake. So I don’t have many people to bounce ideas off of. I’ve found what I feel is a very capable machine shop (tooling wise), but unfortunately this and other shops I’ve talked to local seem to have limited Pontiac experience.
I am by no means an expert and there are a lot of other people on this forum that have much more experience than me on Pontiac engines. That said, I went through exactly the same process you are going through on my 67, so I already found many of the answers.

The main thing you should ask yourself is how fast you plan to spin the engine when you are done. An 8 grand engine will take significantly more work and parts than a 5 grand RPM engine.

One caveat to all my comments. I have built and run my engine, but haven’t driven it yet, so take all this with a grain of salt.

1. I would not block the deck unless it is warped. It will change all the stock measurements. Only do if needed.

2. The rings I used came with the ICON pistons. They were 4032 Alloy.

3. If you are looking at an 8 grand RPM engine, then maybe. A lot of people screw up their heads getting them ported by people that don’t know what they are doing. It sounds like what you are describing, you probably don’t need porting.

4. I used Clevite for all bearings. They are a very good brand and I don’t think you can go wrong.

5. Bracing more depends on how fast you spin it and how hard you will be driving it. Just on street, it probably is not necessary. Strip or high RPM, you will need it.

6. I used Vitron one piece and haven’t had any leaks. Some people have reported bad results with Vitron and have gone back to rope.

7. Yes, the hidden oil galley plug. Just remind your machinist and verify it is in when you get it back from machining. As far as drilling the oil supply hole, my understanding is that is not needed unless you go high RPMs. I would say if you don’t need it, don’t do it.

8. From my reading, the big mistake Pontiac builders make is getting a high pressure pump. Stick with 60 psi. In some applications, there is a need for higher volume, such as when you drill out the oil galley, but if no major changes, stock 60 psi should be fine.

9. I just went with a comp double sprocket chain drive. That should be fine for any basically stock build. I have seen some say to stay away from the double sprocket, but I think that was because of non-stock covers and clearance issues.

10. The Qjets are what the engine and manifolds were designed around, so you should be good. Remember, the more you change from stock, the more potential problems you will run into.
 

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1. You may not need a line bore. May just need a light line hone. May not need either. A good machine shop can check it for you.

The decks need to be squared up with the crank centerline. But, you may not need any extra cut off the decks. The less cut off, the better. It depends on the exact stroke of the crank, exact rod length, and exact piston pin height(compression distance). You can buy custom pistons with any pin height you want. This will allow you to get zero deck height, without cutting extra material off the decks. Auto Tec pistons are the cheapest customs I've found. Shannons Engineering is the cheapest Auto Tec dealer I've found. He must be a volume dealer. A guy at Auto Tec recommended him to me. There are also some Pontiac shops who can order 'em.

https://shanonsengineering.com/collections/ebay-motors-parts-accessories-car-truck-parts-engines-components-pistons-rings-rods-parts/products/auto-tec-small-block-pontiac-400-428-455-flat-top-pistons

2. Don't have the engine bored 'til you choose a piston. Have the machine shop tell you what is the smallest bore size that your block will clean up. Then chose a piston in the smallest bore size that will work, based on the numbers the machine shop gives you. With custom pistons you can usually get them in most any size, in .005 increments. The cheapest Auto Tec customs are made from what they call shelf blanks. They usually stock these in most of the popular sizes, then machine them for whatever engine & specs needed. But, if they don't have a shelf blank in the exact size you need, they can make a new set from scratch. They'll just cost more.

As for rings, I always just used pre-fit TRW moly rings. But, many today recommend file-fit rings, so that the engine builder can file 'em for an exact ring gap. Of course, this is extra cost labor. Total Seal brand rings are popular. DON"T buy gapless rings. The most common ring size is 1/16" top & 2nd rings with 3/16" oil rings.

3. Porting not needed. Probably not worth the expense, for most street guys.

4. I always just used common TRW bearings, without any problems. But, some swear by certain brands & particular types. I'd ask some Pontiac engine builders for their opinion.

5. Voodoo - Hydraulic Flat Tappet - Lunati Power

Voodoo - Hydraulic Roller - Lunati Power

Don't need lifter bore braces with small HR cams. But won't hurt anything either.

6. Most reviews of the one piece seal have been good. But, as said, some prefer the Best Gasket rope.

7. I ran with a hole in that plug, and at least 70psi oil pressure, in my 455 bracket engines. Never had a problem. But, as mentioned, some prefer the 60psi pressure of the M54DS oil pump. I added some shims under the pressure spring, too increase pressure. Some say the larger 3.25" mains of the 455 block need a little more pressure than the smaller 3" main blocks. Opinions differ. Some say it all depends on the bearing clearances.

8. The M54DS is the most popular pump. Some say you should take 'em apart & clean 'em up real good. Butler sells a pump which they have modified, and has a thick bottom plate. You can buy a thick bottom plate from them & other sources. Some have reported leaks with the thin stock plates. Some put 2 stock plates on 'em.

https://butlerperformance.com/i-24453827-butler-performance-pro-60psi-oil-pump-w-pickup-screen-bpi-m54ds-pro.html?ref=category:1234738

http://nitemareperformance.com/high_vol_std_pressure oilpump.html

http://nitemareperformance.com/pro_oilpumpplate.html

9. Well known Pontiac racer, engine builder, & Q-jet expert, Cliff Ruggles, uses & recommends the Melling stock replacement timing set. The chains are plenty strong. And any chain, including the high dollar true roller chains will stretch almost as soon as the engine is broke in. After discovering this, many years ago, I switched to the TRW replacement set. No problems ever.

https://www.rockauto.com/en/parts/melling,3350S,timing+set,5756

The Cloyes brand replacement set is a #C3007k . They're about $25, from an Amazon seller.

https://www.amazon.com/Cloyes-C3007K-Timing-Sets-K-Sets/dp/B000C0AJKY

10. It's a good idea to permanently plug the exhaust heat riser holes in the '67 intake. Otherwise you MUST run a stainless steel separator plate, & the correct gasket set-up. Pontiac had lots of problems with this set-up & discontinued it after only 1 year. Much easier to just block 'em off & run the later type gaskets.

Nothin wrong with the stock type points ignition system. I ran it in all my drag cars back in the 20th century. But, if you want later technology, while keeping the factory look, you can get the Pertronix points conversion set-up.

https://www.summitracing.com/parts/pnx-71181
 

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Discussion Starter #6 (Edited)
Once again thanks for all the insight you guys! This really helps for coming up with a good game plan for the build.
As far as performance requirements the car won’t be getting driven very hard. This is a replacement I bought for my father. He unfortunately sold his original 67’ when he joined the Marines in 69’. Sadly his was destroyed shortly after selling it. He’s seventy now and drives more like a grandma, but still gets a kick out of driving the old car. So I’m more concerned about the reliability/originality look of the engine than an all out fire breather (there is a chance I may be getting two of these engines in the deal, if that’s the case the second one will be). But I would still like to get after it slightly if I steal it for a spin.

Thanks again for all the tips!
 

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Discussion Starter #7
“Colorado 67” thanks for the reply. I get out to Golden a few times a year. I hope to see your car out on the road!
 

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Discussion Starter #8
Thanks for all the detail and links bigD. Talked to Lunati today. Planning on the roller setup. Seem like great guys there!
 

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This is an interesting link on 400hp from a Poncho 400:

400 hp out of 73 pontiac 400

Also this from an excellent Pontiac builder:

408 build for a 69 Judge! Dynoed tonight. - PY Online Forums

With the problems you encounter with the '67 intake, you might check the parts for sale here and on the PY forum for a '68-'72 Pontiac iron intake. I've had good success with the Edelbrock Performer RPM (the std Performer intake is not so good, less power than with the Pontiac stock intake due to tiny passages).

(FYI-bigD has doing and racing Pontiac engines for over 45 years, I respect his advice.)
 

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Thanks for all the detail and links bigD. Talked to Lunati today. Planning on the roller setup. Seem like great guys there!
It has been said by many that most all Pontiac HR lifters are actually Chevy lifters, with Pontiac link bars. Chevy lifters have a lower oil band. Paul Carter uses Hylift Johnson lifters & grinds an oil groove, from the lifter bore oil feed hole, down 1/4", in order to connect with the lower oil band of the Chevy lifters.

I've read that the only HR lifters made, which have the higher Pontiac oil band, are the Comp Cams 857-16 lifters. These are made for CC by Shaver. It has been posted that when CC is out of the Shaver made lifters, they substitute lifters which are made by Morel. These are said to have a part number of 857M-16. They are the Chevy type lifters.

PY Online Forums - View Single Post - 857M-16 Lifters

PY Online Forums - View Single Post - 857M-16 Lifters

None of the cam companies make their own lifters.

So, If you want Pontiac lifters, I'd buy CC 857-16, made by Shaver. Or, buy some other brand & pay the machine shop to grind the oil feed grooves.

http://forums.maxperformanceinc.com/forums/showpost.php?p=5865106&postcount=28

https://www.amazon.com/Competition-Cams-857-16-Retro-Fit-Oldsmobile/dp/B0014F6F36

Just a word about that high hp Paul Carter build. It had SD Performance ported heads, a ported intake, Hylift Johnson roller lifters, and a complete Paul Carter build. I figure that engine would cost well over $10k, & probably over $12k, for the complete engine & dyno time. So, when planning an engine build, you need to keep this in mind, unless you have an unlimited budget.
 

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All good suggestions from everyone and seems you have read a few older postings. Things I would suggest:

I like the 3/4 groove main bearings for a little better oiling.

If you can handle the price, I would get the Butler 60PSI pro oil pump which is improved/blueprinted and tested for flow. I added this to my build, but the Mellings 60 PSI pump is fine if your budget is tight.

I like and purchased the Nightmare machined oil pump shaft. It may require a little fit/clearance, but it is a heavy duty piece. If anything, get an aftermarket hardened shaft at a minimum and they are inexpensive. Standard sleeved & hardened oil pump driveshaft

Deburr the inside of the block at the valley pan/lifters. You will see a lot of jagged edges from the casting. Smooth this all up. Jagged edges can be stress areas and could lead to a crack or if you have a large enough chunk of casting, it could break off which you don't want going into your engine. Never had a problem in not doing this, but if you can, I would grind it smooth. I did do this on my present engine build.

Replace the oil galley cup plugs with threaded plugs to make them more secure. Make sure they do not get inserted to deep and close off any of the oil supply.

You mentioned you did not want to go stroker on the engine, but when you add up separately what it will cost for pistons, rods, bearings, balancing, etc., you may find it a reasonable deal - and you get a new crankshaft. Always build a Pontiac for torque. Bigger cubes will allow you to build the engine less "peaky" than a 400 where it will need higher RPM's. Lot easier to hit your goal of 400HP and lower compression with an additional 67 cubes, but again, it is more about torque.

3-angle valve job.

Get a new harmonic balancer.

Mini starter so you can clock the starter solenoid away from the heat of the exhaust manifold.

Ram Air cast iron exhaust manifolds over headers unless you absolutely gotta have headers. A Pontiac wants to breathe.

A good distributor curve - whether using points or electronic.
 

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"...Get a new harmonic balancer..."


There are lots of high dollar balancers for Pontiac. But, unless you insist on having one with all the timing marks on it, the stock replacement Powerbond 1056N, will work just fine. They're about $45 shipped from Amazon sellers.

https://www.amazon.com/Dayco-PB1056N-Harmonic-Balancer-POWERBOND/dp/B013YN6R38


"...Mini starter so you can clock the starter solenoid away from the heat of the exhaust manifold..."

I've used a couple of the Summit mini starters on my 455 bracket engines. Works great, even when the engine is hot. Eliminated all my hot start problems. But, if you wanna spend more, there are several higher priced brands.

https://www.summitracing.com/parts/sum-820311/overview/make/pontiac

I also use a Ford type starter solenoid, mounted on the firewall. Had a cheap black plastic one that stuck in the ON position. So, I now use the Cole Hersee 24037.

https://www.amazon.com/Cole-Hersee-24037-Intermittent-Solenoid/dp/B001FQL40S/ref=sr_1_10?s=automotive&ie=UTF8&qid=1547494611&sr=1-10&keywords=cole+hersee+starter+solenoid

Lots of racers use the QuickCar version.

https://www.amazon.com/QuickCar-Racing-Products-50-430-Solenoid/dp/B003TTYSH0


"...Ram Air cast iron exhaust manifolds..."

Some say these RARE manifolds are the best. These have the larger 2 1/2" outlet.

https://www.ramairrestoration.com/rm-1-os-d-port-ram-air-style-factory-headers-oversized.html


"...A good distributor curve..."

Some think the mechanical advance needs to begin increasing the timing from about 1000 rpm or slightly higher, and achieve max advance by 3000 rpm. In order to accomplish this, the advance weights need to be clean and adequately lubricated so that they will move smoothly & completely.

The rate of advance is then regulated by the advance weight springs. Lighter springs will allow the weights to advance timing sooner. There are kits which have lighter than stock springs. Most do not recommend using the lightest springs in the kit, because they don't seem to last very long. You may be able to get your desired curve by using one stock spring & one weaker spring. Will just have to try different spring combos to see what works for you.

You may need to add a positive advance stop to your dist. For example: if you want to have 15° initial advance at idle and 35° total advance, but your dist will advance 24°, if you set your initial at 15° you'll end up with 39° total -- 15° + 24° = 39°. In that case, you'd need to make a stop that would limit the amount of mechanical advance by 4°. There are several ways to achieve a positive stop.

Most street guys like to also use a vacuum advance, for street cruising rpm. Some stock vac advance units add too much advance. But, there are adjustable vac advance units which will allow you to add only the amount of vac advance you want. There is a Crane brand kit which has the adjustable vac advance and 3 pairs of advance weight springs.

https://www.amazon.com/Crane-Cams-99601-1-Adjustable-Advance/dp/B000CIO2KY

On many parts, you can save a few bucks if you buy from Summit, with an order of $99 or more. But, for smaller orders, Ebay or Amazon usually has the best shipped price. If price is not an issue, just ignore this statement.

There is a LOT of online info on setting your ignition curve.

https://www.google.com/search?q=how+to+set+your+ignition+curve&rlz=1CAHKDC_enUS777US777&oq=how+to+set+your+ignition+curve&aqs=chrome..69i57j69i64.20712j0j4&sourceid=chrome&ie=UTF-8

Or, you can send your dist to guys who will completely rebuild it & set the curve for you. Some of these guys are not cheap, at all. But, if your dist has some severe problems & you wanna use it, that may be an alternative to buying another dist.

Here's one of the high dollar rebuilders. He posts on the PY forum.

http://forums.maxperformanceinc.com/forums/member.php?u=143447
 

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Discussion Starter #13
Thanks you guys, it’s a wealth of information. I really appreciate the response!

I was planning on buying the upgraded oil pump as long as you guys have had good success with them (sometimes it’s worse off going aftermarket).

The exhaust. I was trying to stick with the original for correctness but if I need to ditch the originals for lack of flow so be it.

Good call on the balancer! I was just reading a horror story of a reused one that wiped out a new rebuild.

Jim, the cup plugs your talking about are those the ones at the front of the block? Thanks for the heads up about the deburring. This wasn’t brought up with the machinist.

If I go the stroker route which one do you guys prefer? I’ve read some bad reviews about the Eagles having some bad machining? Maybe Scat as an alternative?

Price is always a concern but I’m more than willing to build it right. This has been a drop in the bucket compared to owning an airplane, and has been every bit as enjoyable.
 

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"...If I go the stroker route which one do you guys prefer? I’ve read some bad reviews about the Eagles having some bad machining? Maybe Scat as an alternative?..."

The only problems I've read about are with the Eagle CAST cranks. I'd go with a Forged crank. But if you prefer Scat, Butler only charges about $50 more.

The Butler 4.25" stroke assemblies are very popular. Lots of options.

https://butlerperformance.com/i-31643243-butler-ross-461ci-4-155-balanced-rotating-assembly-stroker-kit-for-400-block-4-250str.html?ref=category:1459542

Most say that there is not a big power difference in the 4.25" stroke and the 4.21" stroke. The 4.21" stroke assemblies have stock Pontiac length rods, and Pontiac size rod journals. The 4.25" assemblies have BBC size rod journals, and longer rods.

https://butlerperformance.com/i-24453658-butler-performance455-462ci-balanced-rotating-assembly-stroker-kit-icon-or-ross-for-400-block-4-210-str.html?ref=category:1459542

WARNING ! If you build a stroker, it will have about 500 or more torque, at about 3000-3500 rpm. This kind of torque can easily break drive line parts at WOT, IF your rear tires get good traction. My home built 455's broke several auto trannies & a couple of 10-bolt rear ends. Big torque is fun, but can be destructive.

Some choose to go with a 4" stroke. This would produce slightly less torque, in a similar build. You'd also need less dish in your pistons.

https://butlerperformance.com/i-24591342-butler-performance433-440ci-balanced-rotating-assembly-stroker-kit-for-400-block-4-000str.html?ref=category:1459542

If you decide you'd rather not trust your area shops with your shortblock build, you can buy a crate shortblock from OK, & have it shipped. Here's a link to a basic build. You can add to this a forged crank, in the stroke you choose, & dish pistons, as extra cost options. Len will furnish the block. Or, you could send him yours. I've read some good reviews of Len, from some of his customers.

http://lenwilliamsautomachine.com/455_Short_Block.html
 

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The oil galley plugs are up front on each side of the cam tunnel. 1st picture shows you where they are located. 2nd pic shows from a side view the pipe plug. The hole is tapped and pipe plug installed. You don't want too deep, but deep enough, and make sure no interference with the cam sprocket. 3rd pic shows the "hidden" rear oil galley plug as seen looking down the distributor hole. Just want to make sure it is not forgotten during re-assembly. See pics in next reply as they did not upload.

With regards to the crank, early on there were issues with the aftermarket cranks - made in China and the quality was a little sketchy. From my reading, this was improved and corrected and there have not been any issues in years.

You can go forged crank as bigD points out, but it is not really necessary for street unless you were to really spin higher RPM's with a stroker engine which would also mean much better flowing heads to take advantage of the higher RPM's.

Looking at the Butler website, they offer the cast & forged crankshaft in 4.00" stroke and 4.25" stroke. The 4.00" stroke (same as the 421CI) with .030" over pistons gives you a 433CI. The 4.25" stroke gives you right at 460CI.

The forged crank offering bigD points out does come in a 4.21" stroke and with a .030" overbore would give you 455CI using the stock Pontiac length 6.625" connecting rods.

My opinion here. I would go with the Eagle 4.25" cast crank with 2.20" Chevy rod journals. Why? Cast will be fine for the RPM range the engine will see. So let's add it all up if you were to purchase parts individually.

Eagle cast 4.25" stroker crank. Cost $290 @ Summit. I like the Eagle SIR I-beam Big Block 6.8" length forged rods. Cost $329 @ Summit. I cited Summit because shipping is listed as free over $100, even on the crank according to their website. So total so far is $611 for crank & rods.

Pistons will need to be custom and that means forged and will be pricey - as most all forged pistons are not inexpensive. Butler offers Ross custom pistons with pins/rings for the above application for $699. You will need dished pistons to match your head chamber cc's to try and get down near 9.0-9.3 compression. Total is now $1,310.

Bearings are $70 for 3/4 grooved mains & $57 for rods. Total now is $1437.

Balancing will run you about $250. Total now is $1687.

A complete 4.25" Eagle stroker rotating assembly, balanced, from Butler is $1598. Not only is the price lower, you know all the parts will work together. The shipping costs will add a few more dollars and may cause it to be slightly higher than piecing the assembly together.

The added stoke is also your power adder though the additional cubic inches and longer stroke torque. Keeping the 400 stock and do some upgrading in a few areas like SIR forged I-beam rods, forged dished pistons, and balancing and the assembly will be much cheaper, but then you will need to pull more HP/TQ from a bigger cam which will most likely mean running the engine to a higher RPM range - which is still doable and may sacrifice low end power. For a street engine, you want the power/torque in the lower-to upper mid range RPM's; stop light to stop light acceleration. A hot cam in a 400CI will be milder in a bigger inch engine so you will still have good power, but a better mannered engine.

Here is a real life comparison. A car magazine tested side-by-side a 1970 Ram Air IV GTO and 455 GTO with Ram Air and AC.

The RAIV had close ratio 4-speed, 3.90 gears. Factory advertised 10.5 compression, 366HP @ 5100 RPM, 445 TQ @ 3600 RPM. Test weight 4230 pounds.

The 455 had a TH-400, 3.55 gears. Factory advertised 10.25 compression, 360 HP @ 4300 RPM, 500 TQ @ 2700 RPM. Test weight 4455 pounds.

Performance numbers went like this:

RA IV 1/4 mile 14.60 @ 99.55 MPH shifting @ 6100 RPM's
455 1/4 mile 14.76 @ 95.94 MPH shifting @ 5400 RPM's

RA IV 0-60 6.0 seconds
455 0-60 6.6 seconds

Passing speeds
RA IV 30-70 MPH 5.0 seconds
455 30-70 MPH 5.3 seconds

Gas mileage
RAIV 8.9 MPG
455 11.8 MPG

My guess is that if the AC were dropped that the 455 would have been about equal in performance. I did use the Wallace 1/4 mile calculator and then used the lighter weight of the RAIV car to get a faster 1/4 mile time of 14.51 seconds showing the 455 would have beat the RAIV car! Better street manners & better gas mileage at higher TQ and much lower RPM's.

Again, my opinion, and always best to put together a plan with your machinist or engine builder. :thumbsup:
 

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"...Looking at the Butler website, they offer the cast & forged crankshaft in 4.00" stroke..."


The way I read it, the 4" stroke crank is forged only. I think the only cast crank is a 4.25 stroke.

" New Forged Crank 4.000" Stroke "

https://butlerperformance.com/i-24591342-butler-performance433-440ci-balanced-rotating-assembly-stroker-kit-for-400-block-4-000str.html?ref=category:1459542

Here's an Eagle crank thread from PY.

Eagle Cranks - PY Online Forums

Yes, I believe you are correct. I looked at just the crankshaft as an individual piece and Butler does list a 4.0" cast crankshaft for $339. (Description: New Pontiac Cast Crankshaft 3.00" Main Journal Size 4.000" Stroke 2.200" BBC Rod Journal 6.700" Rod Length), and also looked at the rotating assembly which had the forged crank.

However, I missed the "Not Available" just above the price as I looked at it quickly. So the only offering in the 4.0" stoke crank at this time seems to be the forged piece as part of the rotating assembly they have. No idea why they have it listed if it is not available or has been discontinued. :confused:
 

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Discussion Starter #19 (Edited)
Once again thanks for all the info and detail!

I probably should have mentioned this earlier but the car has the 4 speed Muncie, an 8.2 BOP that I just put a posi in and swapped out the 3.55 for a 3.36 for a little better highway performance. The trans will be getting a full rebuild while the engines out and a balance on the driveshaft. Is there any reason to go to a chrome alloy style U-joint? I’ve always used the cheaper ones hoping they would be more like an electrical fuse. Breaking before something more costly breaks.

The block- I did look around at just purchasing a new built engine or block, but would like to build it local so I can make sure all of the little improvements you guys mentioned can be added. That’s why your advice here is priceless. You have done the personal leg work. I wish they would start a separate index just for you guys to list your proven builds. Thanks for the shots of the block plugs-that is on the to do list!

A question about the roller setup. If I go the total roller cam/rockers can I than drop the Zinc oil and run a standard synthetic?

Intake- once again I’m trying to keep this as close to original looking as possible. “68’ GTO” mentioned about changing this out for a later model. I happen to have one of these around the garage and there’s a significant difference in appearance. Is this imperative to upgrade?

The Heads- I did look into the SD’s they look like they have a way to really open the 670’s up but at the same time is this really necessary for a street/400 hp build? Or just the plan of a good refresh and roller setup be good enough?

Crank-The more you guys talk about the stroker setup the better that’s sounding. Have any of you bought the pre-balanced setup? We’re they set up/balanced properly from the factory?
The link about the Eagle failures is similar (and tragic for those owners) to what I had read elsewhere. But about the same vintage of posting(about 7yrs ago). I would hope by now if there was an issue it has been addressed by now.

Thank you also for the distributor info..

Hope to pick the engine up tomorrow and start the tear down. Weather permitting, it’s snowing like crazy here in Utah!
 

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"...If I go the total roller cam/rockers can I than drop the Zinc oil and run a standard synthetic?..."

Yes.

"...Intake- once again I’m trying to keep this as close to original looking as possible. “68’ GTO” mentioned about changing this out for a later model. I happen to have one of these around the garage and there’s a significant difference in appearance. Is this imperative to upgrade?

The '68-'72 intakes were very similar to the '67. They just didn't have the exhaust heat holes & the "smiley face" "hot slot" under the carb. But, I'd use the '67 intake before I'd use a '73-'79 version. The later intakes will bolt up & work, but they all have EGR holes on the pass side that must be plugged. And, the '73-'74 models had a huge sump underneath, requiring a '73-'79 valley pan. It also makes 'em heavier. I'll try to post some intake pics.

"...The Heads- I did look into the SD’s they look like they have a way to really open the 670’s up but at the same time is this really necessary for a street/400 hp build? Or just the plan of a good refresh and roller setup be good enough?..."

Porting, for the power level you want is not needed. Whether to go with stock stroke or stroker will have to be your call. 375hp is easy, with stock stroke & a HFT cam. 400 is easy with a 4" stroke & HFT cam. Over 400hp, plus near 500 torque is easy with a 4.21 or 4.25 stroke & HFT cam. Correct HR cam can easily increase hp 15-25hp, or maybe a little more, & still be very streetable.

I'd consider the cam a major decision. Millions of Pontiac engines have lived long lives with hft cams. But, when the non-USA made hft lifters came along, there were lots of cam failures. Many blamed it on the oil, because of the reduced zinc levels. Anyhow, there are lots of Pontiac engines still being built with hft cams. You just need to use oil with the zinc additive, AND break the cam in correctly. This means running the rpm up to at least 2000, immediately after starting, & keeping it there for at least 20 minutes. DON"T LET IT IDLE. Best to vary the rpm, above 2000 & back down again, rather than leaving it steady. Some vary the procedure slightly. You can Google something like "how to break in a hydraulic flat tappet cam", and get lots of detailed explanations, & probably some YouTube videos.

But, lots of guys nowadays are choosing the HR cam set-up. This can easily cost from $1000 to $1500 more than the hft cam set-up, or even more, depending on the lifters & rockers you choose. Advantages are: a little more power, and not having to worry about cam/lifter break-in or getting enuff zinc in the oil. I assume that the longest lasting rockers would be the Crower stainless steel units. But, they are also probably the highest priced. The scorpion Endurance series alum rockers might be a good choice. Lots of guys believe in the Harland Sharp brand rockers. Avoid PRW and any other cheap Chinese made rockers. There have been lots of failures reported.

https://butlerperformance.com/i-24453825-crower-pontiac-enduro-stainless-steel-rollerized-1-5-rockers-set-cro-73627-16.html

https://www.summitracing.com/parts/scc-scp3052/overview/make/pontiac

https://www.jegs.com/i/Harland-Sharp/851/6001/10002/-1?CAWELAID=1710738642&CAGPSPN=pla&CAAGID=15769068431&CATCI=pla-212327193431&CATARGETID=230006180037476134&cadevice=c&jegspromo=thirdparty&gclid=Cj0KCQiAj4biBRC-ARIsAA4WaFiun3jAq6B97LTXwsMj9YQR18ophtqJUC8LdITLSILMlr_Bjy_4XbAaAi3PEALw_wcB

"...Crank-The more you guys talk about the stroker setup the better that’s sounding. Have any of you bought the pre-balanced setup? We’re they set up/balanced properly from the factory?..."

I assume you're referring to those that were balanced by Eagle & NOT Butler. I'd pay the extra cost & go with a Butler assembly. But, I'm sure there are quite a few who have had good luck with the Eagle factory assembly. KRE can also supply you with a balanced stroker assembly. Their price list may not be current. They also still show a cast 4" stroke crank. Don't think those are still made. Have to add $200 to the listed price, for balancing. They come with KB Icon pistons. Can upgrade to Ross, for extra cost, but the Icon pistons are considered good quality. KRE is a well respected Pontiac engine builder.

Kauffman Racing Equipment

There are quite a few Pontiac engine builders who can set you up with a balanced stroker assembly. Here are a few.

https://www.facebook.com/PaulKnippensMuscleMotors/?ref=br_rs

http://www.dcimotorsports.com/services/pontiac-v8-engine-builder/

http://www.sandovalperformance.com/rotating-assemblies


"...Eagle failures...I would hope by now if there was an issue it has been addressed by now..."

If you wanna take a chance on an Eagle cast crank, that's your decision to make.

Here are the pics I mentioned. As you can see, there's not much difference in the '68-'72 intakes.
 

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