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1970 Pontiac
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It's a better engine/block than a 428-455. Much stronger mains and better integrity. The only Pontiac block that is stronger is the '59-'63 389 block.

You basically have the best 400 block Pontiac made....best iron, highest nickel content, best casting, and best machining. (1967--74 blocks)

The big journal 421-428-455 blocks have rear main seal issues and crank journal/main saddle issues at RPM.

I would much rather run a 400 or a stroked 400 block. I've been driving these cars for the past 45-ish years steadily. YMMV.
Now I know why army is wanting one to build ! 馃槀馃槀
 

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1970 GTO / 400 / 4 speed
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208 Posts
Discussion Starter · #62 ·
I guess the 2k mentioned by @Duff on the first page is a good place to go out based on all I'm seeing. Something is worth what the local market will bare. If it's fair, someone will jump. If not, I'll get the message and adjust. You can always adjust down if need be but can never go up... Oh, and just remembered... It will come with both a flywheel and a flex plate.
 

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2k is more than I would pay but someone else is likely to pay that price. You have a very desirable engine for a build. Considering the skyrocketing costs of our 'build back better' economy, 2k is not outrageous at all, IMO. It would be a win/win for you and the buyer. So would $1500. GLWS.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #64 ·
2k is more than I would pay but someone else is likely to pay that price. You have a very desirable engine for a build. Considering the skyrocketing costs of our 'build back better' economy, 2k is not outrageous at all, IMO. It would be a win/win for you and the buyer. So would $1500. GLWS.
Thank you very much for all your insight. Will see what happens in a few weeks when the 400 comes out and comes home. I've already worked up a draft on FB marketplace and have taken photos and videos.
 

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I'd price it high and hope for "that person" who really wants that year/numbered block. If you don't find that buyer you get to keep it and never feel bad you sold it for less than you could have. Did I mention you may get to keep it. I'd keep it, hands down.

If my 67 born with block would be junk...I'd pay $1000 more for the right month and year numbered running engine assembly compared to one that was just close. Even if I just needed a block. All the extra parts are great to have as spares or sell them off piecemeal and make most of the money back.

If you think a good price is around $2K, start at $3K. This gives you room to haggle, keeps the tire kickers at bay, and a good running engine carries some extra weight.
 

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Does the fact that it's complete from pan to air cleaner with all accessories/brackets/pulleys and the fact that it's currently running help?
How many miles on the engine?

Has it been rebuilt?

How many miles on the rebuild?

Who/what shop rebuilt it?

Receipts?

Oil pressure at idle and 2,600 RPM's?

Compression test of all cylinders?

Do you guarantee it against any cracks in the heads or block if it gets taken to a machine shop for magnafluxing/rebuilding?

Do you guarantee the engine if I just drop it in my car and use it like that?

Depending on your answers, price between $900.00 for a builder - no guarantee; up to $1,800.00 drop in as is and guarantee.

The shortblock may be of value to someone wanting a WT block along with the May build month. The heads would not be of interest to the.
 

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FWIW, I paid $500 for a (poorly) running standard bore 1973 400. Complete motor, but I only wanted the block. This was about 8 months ago. If someone wants that particular date or casting code, then it would be worth more to them. If they are just looking for a builder, then less.
 

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It's a better engine/block than a 428-455. Much stronger mains and better integrity. The only Pontiac block that is stronger is the '59-'63 389 block.

You basically have the best 400 block Pontiac made....best iron, highest nickel content, best casting, and best machining. (1967--74 blocks)

The big journal 421-428-455 blocks have rear main seal issues and crank journal/main saddle issues at RPM.

I would much rather run a 400 or a stroked 400 block. I've been driving these cars for the past 45-ish years steadily. YMMV.

It's a better engine/block than a 428-455. Much stronger mains and better integrity. The only Pontiac block that is stronger is the '59-'63 389 block.

PJ: Wrong. 389CI 425A 4-bolt main, SD 421 4-bolt main, 428 4-bolt main, 455- 4-bolt main, RA IV 400 4-bolt main, SD 455 4-bolt main.

Any block is only as good as the build and how it is used. If you take a stock 455 from grandma's car which only has a factory oil pump pressure of 40 PSI and you proceed to hammer on the engine pushing past that 5,000 RPM line, the engine damage is not because it was a weak block or had larger main journals. Pontiac actually cross drilled the 455 cranks to supply constant oil to the rod bearings - but you have to have enough oil flow and pressure when you start using grandma's engine like a race engine. The 428 4-bolt main bored to 440CI was one of the best race engines - more cubes than the 400CI and it would spin more RPM's than a 455.

The big journal 421-428-455 blocks have rear main seal issues and crank journal/main saddle issues at RPM.

PJ: Wrong. Seal issues can mostly be attributed to rebuilds (including 400's) using the 2-pc or 1 piece aftermarket viton seal, rebuilds where align boring has altered the rear seal main cap causing it to become more oval than round - but can be correct by a good machine shop, and later production 455's that may have had the rear main cap incorrectly machined according to a Pontiac dealer bulletin.

Very little difference in a stroker 400 or a 455, nearly the same stroke and a small difference in bore. In a low rpm street engine the smaller mains won't really help enough to be noticeable. You can find a 400 much easier than a 455. In Either case you want to use light pistons, rods, and pins, and good oil pump/pan and they will both live long miles.

The 400 blocks are said to be a little stronger with 1/8" more meat in the block, around the mains, and the main cap thickness. Add a set of ARP main cap studs or aftermarket 4-bolt main caps to a 455 and I see a stronger bottom end than a stock 2-bolt main 400. Apples to Oranges here.
Each cubic engine has its limits and each can be damaged/blown up in stock form when these limits are exceeded. Each cubic inch engine can be built to perform beyond the stock configuration by using correctly designed and matched aftermarket parts intended for HP/Race use. Any build has to be looked at realistically and the builder/owner has to know the limits of that build even when they invest 10's of thousands of dollars.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #70 · (Edited)
How many miles on the engine?

Has it been rebuilt?

How many miles on the rebuild?

Who/what shop rebuilt it?

Receipts?

Oil pressure at idle and 2,600 RPM's?

Compression test of all cylinders?

Do you guarantee it against any cracks in the heads or block if it gets taken to a machine shop for magnafluxing/rebuilding?

Do you guarantee the engine if I just drop it in my car and use it like that?

Depending on your answers, price between $900.00 for a builder - no guarantee; up to $1,800.00 drop in as is and guarantee.

The shortblock may be of value to someone wanting a WT block along with the May build month. The heads would not be of interest to the.

Jim, as you probably know, I just bought the car a couple months ago and honestly can't answer most of those questions. The previous owner also didn't have that info as he sold it the way he bought it in 2012. He bought it with intention of doing what I'm doing but never had the time. I saw his annual inspection receipts that listed his mileage. He basically took it to get a sticker once a year and back in the barn it went. Perhaps you're trying to point out the questions a potential buyer might ask?

As to the ones I can answer... I have not done a compression test but will probably do that before pulling the motor. Oil pressure at 2600 is 60. On the the guarantee, no, of course I can't guarantee anything... nor would I even if I could. It's a used motor and someone could throw nitrous on it and/or over rev it on day one and blow it up. That's just one scenario out of many that I can think of but you get my drift. All I know is I've been driving it almost daily since I bought it and other than the carb and ignition needing tuned, I've had no issues.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #71 · (Edited)
Forgive me but I went back to the beginning of your thread but don't see anything, why did you have a 428 built instead building/stroking the 400 that you're going to sell ?
My original plan when I bought the car a couple months ago was to (over)build the 400 that's in it. So, I got to putting together a dream parts list and getting everything in my cart(s) to order. First reality check was something mentioned a few posts back. The cost. Holy lord was it adding up quick vs. a SBC build. However, that wasn't insurmountable. Availability was. Roller cams are near impossible to find and they are indefinitely backordered from most companies I was considering. To have a back order date is one thing but to be told over and over again that they couldn't even give me an estimate was unsettling. Then aluminum heads. Kauffman is out 4 months. Edelbrock is out til late December too. And that's where the short list ended. So, in lamenting my situation with my machine shop / engine builder, the owner asked me a question that took me off guard. He said, hey, if you don't want to wait until spring, would you consider a built 428? I asked why? He said he had built one for a customer right when Covid started. The guy provided the engine and many parts. He then did all the work and supplied the remaining internals and built the motor. He called and left a message that the motor was done. He called again once a month for a year. Then once every 6 months for the next year and a half. He never found an obituary or anything but assumes the gentleman passed away. So, after a couple of years of his money and shop space tied up, he's decided to sell it. At first I was reluctant as I wanted my motor exactly the way I wanted. But then I got to thinking about 2 things... "Exactly the way I want" would cost me 3 times as much and I'd be waiting to do it til next year. Having the attention span of the average gnat, I dropped a deposit on the 428 along with a few parts to make it my own and we're off. The builder wants to run it in on his stand before I pick it up and the shop doing the R&R is out a couple of weeks so that's as long as I have to wait as opposed to 2023. So, that's how I ended up with a 428...
 

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Ah ok, makes sense and maybe I missed that. When my motor went south I had sticker shock too, if I wanted 500hp it was around 15k and that was in 2018! So when I saw this Butler 461 on ebay for 8k ( negotiated it down to 7500.00) with receipts and dyno sheet I jumped on it. I feel very fortunate to have found it, right time right place 馃憤
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #73 ·
Holy!!!! That's a steal! Congrats on that find man... I was looking at a full Butler build too but that was pushing 20k. I got the 428 for 5k. No, it's not a 600+HP monster but that other 15k can paint the car at some point... Or buy that square body GMC the wife keeps asking for...
 

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Holy!!!! That's a steal! Congrats on that find man... I was looking at a full Butler build too but that was pushing 20k. I got the 428 for 5k. No, it's not a 600+HP monster but that other 15k can paint the car at some point... Or buy that square body GMC the wife keeps asking for...
You got it, it dynoed at 472hp 526tq and the guy decided he wanted 600hp for his Firebird and didn't install it. I changed out the intake to a Performer RPM, put an 850 Quickfuel and 1.65 rockers so maybe I'm close to 500hp and believe me it's scary enough. I have big drag radials and lift bars but still can't keep it straight. Big numbers always sound good at the car shows and I'm guilty somewhat but I'm perfectly happy with it.....unless it doesn't perfom well at the track 馃ぃ I also had to put a ton of money into the driveline to support 500hp like a 3K trans, 500.00 driveshaft a 2100.00 rear end. So down the rabbit hole deeper and deeper...my wife works 32 hrs a week and tells everyone it's for my car....I plead guilty your honor and hope the court has mercy on me.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #77 ·
Sounds like our wives are similar. Mine says... "Everyone always thinks we have money because of all we spend... If we're so rich, how come I have to work so much?"
 

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Exactly, and up until the last few years when my back went out I did everything myself on the house, neighbors would spend 50k on there basements or paver sidewalks but maybe that's why my back is not great so I have to start writing checks now. Also we were smart with our money and didn't live beyond our means since we've known each other but people don't see that and we've lost friends over it. You mentioned the Ford your wife wants I think you should suprise her with it trust me. I felt so guilty I found her a 2013 purple Challenger that she has dreamed about for a Christmas suprise. I call it the purple IRA but I have no more guilt and I have never seen her so happy and cry so much, not even at our wedding 馃槃 of course there's the shoes and close that come every week...and a few diamonds and the beach once a year but I'm sure I'm still ahead 馃槈 Well I've certainly derailed this thread, sorry.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #79 ·
Nah, it's all good man. Sounds like we are both lucky men. I am extra blessed as my wife is into the things I am into. When brown santa brings cardboard boxes to the door she demands to know what's in them. Not because she didn't approve the purchase but because she's as into the build as I am.

As to the truck, it's on the list. I keep scrolling through FB nightly trying to find a second "barn find...."
 
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