Recipe for a 67í 400 hp build? - Pontiac GTO Forum
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post #1 of 50 (permalink) Old 01-15-2019, 08:35 PM Thread Starter
 
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Recipe for a 67í 400 hp build?

Hello all,
Iím 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?
Iíve got a 67í GTO w/numbers matching engine Iím parking under my shop bench to preserve. To replace it Iíve found a 67í 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 havenít been able to find much on this one (or maybe I missed it?)
Any help is much appreciated!
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post #2 of 50 (permalink) Old 01-15-2019, 09:27 PM
 
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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...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-3164...tegory: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 !

Last edited by bigD; 01-16-2019 at 07:13 AM.
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post #3 of 50 (permalink) Old 01-16-2019, 09:28 AM Thread Starter
 
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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.

Last edited by Dukes67; 01-16-2019 at 09:45 AM.
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post #4 of 50 (permalink) Old 01-16-2019, 01:31 PM
 
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Originally Posted by Dukes67 View Post
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 Iím planning on the following beside the normal clean and inspection.

1.Line bore, block the deck. Iíll 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 donít recommend porting the heads?

4.Polish/balance/chamfer the crank (hopefully it wonít need too much, itís from a low mileage family car). Do you have any bearing preferences throughout the engine ?

5. Iíll 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 Iím still learning on these Pontiacís)

6. Rear seal (a small but big deal) Iím 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 ďmust be thereĒ 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. Iíd 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 donít have (or I havenít found) much of a Pontiac following here in Salt Lake. So I donít have many people to bounce ideas off of. Iíve found what I feel is a very capable machine shop (tooling wise), but unfortunately this and other shops Iíve 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 havenít 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 donít know what they are doing. It sounds like what you are describing, you probably donít need porting.

4. I used Clevite for all bearings. They are a very good brand and I donít 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 havenít 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 donít need it, donít 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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post #5 of 50 (permalink) Old 01-16-2019, 01:42 PM
 
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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/colle...at-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-2445...tegory:1234738

http://nitemareperformance.com/high_...20oilpump.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/me...iming+set,5756

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

https://www.amazon.com/Cloyes-C3007K.../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

Last edited by bigD; 01-16-2019 at 02:43 PM.
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post #6 of 50 (permalink) Old 01-16-2019, 03:12 PM Thread Starter
 
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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!

Last edited by Dukes67; 01-16-2019 at 04:06 PM.
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post #7 of 50 (permalink) Old 01-16-2019, 04:35 PM Thread Starter
 
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“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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post #8 of 50 (permalink) Old 01-16-2019, 05:14 PM Thread Starter
 
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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!
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post #9 of 50 (permalink) Old 01-16-2019, 07:13 PM
 
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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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post #10 of 50 (permalink) Old 01-16-2019, 11:21 PM
 
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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/...6&postcount=28

https://www.amazon.com/Competition-C.../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.

Last edited by bigD; 01-17-2019 at 02:50 PM.
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