bill3969

I have an 89 5.7l TPI in need of major repair. I let a guy "upgrade" it for me and after 3 months of excuses I saw him putting pistons in my block with a hammer and no ring tool. Needless to say, I have to tear it all down, and start over. Meanwhile my IROC is out of commision. What I need to know is what blocks are the same as the one in my car. I intend to use my setup from heads up, but want to replace the shortblock with another untill I can get mine built. At least I will be able to drive it untill I can afford all new parts.

robert1

iTrader: (3)

Any Chevrolet small block will work I'd say. They're all physically the same size. The only difference was in 1987? when they went to roller cams and the one-piece rear main seal.

80Sierra

Trucks did not have roller cams until the mid 90s (like 94+ sorta thing)

But yeah, as mentioned, the only major difference in the blocks are the sizes of the oil pressure ports by the dizzy & above the oil filter, if the block has been machined for a mechanical fuel pump or not (block off plate can fix that issue) single peice rear main seals after 87, along with center bolt heads in 87.

Personally, I'd be looking for a truck block with the casting number 3970010 with 4 bolt main caps. These blocks have extra nickle in their casting, and wear far better than most blocks.

The engine itself in it's stock form isn't that impressive, about 170 horse at the crank depending on the year (the newer it is, the less powerful, this block was used from 69 through 80). The heads absolutely suck, they flow terrible, and crack easy with overheating, not to mention a large 78 cc combustion chamber. The pistons are dished aluminum pistons. Between the two, you typically have a compression ratio of about 8.5:1. However, with a new set of flat topped pistons, nice camshaft, and a good set of L98 heads will have you in the 280 - 300 horse

shaggy56

Last I heard they didnt make high nickel blocks after 1970 so your odds of finding one is highly unlikely. If you find any block with that casting number it wont be any different than any other block. I can link you to a GM foundry employees thread if you want the facts about this.

CrazyHawaiian

I know its not exactly cheap but Fast 5.0 on E-bay sells rebuilt 0 mile bottom ends (87+ roller, 2 or 4 bolt main 1 piece rms) for under $800 good up to 385hp and comes with a 12month warranty. This is the route I'm going on my next build for my IROC-Z (gonna match that up w/ vette 113 heads and a HSR). Probably more than what you wanted to spend though considering your situation. Figgured I would throw the option out there anyway ...

bill3969

That is good to know, the older blocks I can get very cheap. How do i fix the oil ports? Can I just grind them out and be ok? Did the older blocks have the emissions passages that I need? Roller cams? I saw him put in standard hydraulic lifters. Another reason I wish I could find him to sue him.

80Sierra

Thats odd, while several engines shared that casting number, you can identify a high nickle block by looking for an 010 behind the timing chain cover. My 74, 76, and 80 have all had em (unless I was misinformed about how to identify a high nickle block in the past)

Actually, if you wouldn't mind posting that link up, it'd be worth a read!

shaggy56

From what the foundry employee had to say was that at one time it had been true but it would have been ridiculous for the foundry to throw out perfectly good mold cores so they still existed after 1970. The actual high nickel content blocks had been discontinued after 1970. The only blocks with high nickel after 1970 would have been the bowtie version or any specialty block made by GM.

Heres the original thread.

http://www.nastyz28.com/forum/showthread.php?t=10896

Mcdamit

Umm yeah your engine is toast, you can more or less use any block pre-Lt1. If it was configured for a mechanical pump, a $5-15 block off plate can be used.. I'll be back in a minute
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Edit: Just find a 350 smogger block or pay a grand for a brand new GM short block. Swap your parts and install a camshaft.

80Sierra

Very interesting, thanks for the link!