I recently bought a '90 camaro RS, but (brain that I am) I didn't check the engine to make sure it was the original, and, guess what! it's not. I've been all over it, all under it, inside it, and all I can find is an AC Delco printed metal sticker which states it's a rebuilt engine for GM with a part number and a few specs. I tried looking up the numbers, tried looking up Delco rebuilt engines, so far I've found nothing... I realized it wasn't the right engine when I went to work on the A/C unit and realized this engine has a completely different belt configuration than the one shown in my Haynes manual. Any help would be appreciated.

 

Sounds like a basic replacement engine. You're not going to learn a whole lot about it. You can get a casting number off it to see if it's at least a 305 or 350 casting. The suffix numbers stamped on the pad in front of the passenger head have probably been machined off so you'll never know what the block originally came in, if it was even a production block.

If there's any numbers on the GM data plate, your GM dealer "might" be able to find some information about it.

I've installed GM replacement engines before. It sucks when the original engine uses metric fasteners like the bellhousing bolts, starter etc and the replacement engine uses SAE fasteners.

 

Thanks... you're talking about the casting numbers under the valve covers? I was advised against pulling those off... :P i'm kind of an engine n00b. Is there a reason not to yank those off?

 

The casting #'s under the valve covers only tell you about the heads, what you need to find is the block number located on the top rear drivers side. depending on year you could also see in that location a 5.0l or 5.7l .

 

Quick update: I was unable to find the casting numbers. However, I DID find out that the radiator was replaced with the engine, and matched up the numbers on the belt config and found out that the radiator and belt config sticker (which actually matches the engine) are for a 350, so I'm assuming it's a rebuilt 350. I can post pics, but I expect that wouldn't help anyone tell me if i'm wrong?

 

Pictures won't help since externally all SBC engines look the same. A 350 rad can be installed with a 305 if the proper rad isn't available. It's easier to keep one rad size in stock to fit all applications. Never assume based on other observations. Without casting numbers, there's no proof on the actual engine size.

 

u can always tear it down and start measuring