Anyone know how I can verify if an engine is a real 327? It is in an '80 Elky, and no, it's not the original. As we all know, most small blocks look about the same on the outside. So, what is a reliable way to determine what a replacement engine is? How can you tell a 305 from a 327 from a 350, etc? If it was original, that would be easy, but in this case, the engine is not. Is there a block serial number that would reveal c.i.d.? Thanks for any help!

If you can check the stroke that is the best way. (this sucks) Pull a plug and stick a wire through the hole and see how far it goes from top to bottom. 327 stroke is 3.250 and 305 and 350 strokes are 3.480 Good luck
George

ps a 327 and 350 share the same bore just different stroke and 305 and 350 share the same stroke but different bore

If you can see the engine stampings you may be able to decode it that way. Usually they are on the back of the block on the passenger side so you may need a mirror and a light to get them. Sometimes they put stampings on the side of the block too down towards the freeze plugs.

Thank you for the tips. I'll take a look for block stampings first, as that would def. be easier than checking the stroke. Thanks, bigdog for the info, I didn't know 350 & 327 had the same bore. So I suppose it's possible for someone to take a 350 block and build it as a 327 with a new rotating assembly, the same way you can take a 350 and stroke it to 383.

If you follow the history then the 350 is a stroked 327. IMHO then the 400 is a complete new engine due to the siamesing of the cylinder walls in the block. Someone I know runs a 332 inch small block that turns 9750rpm's at the end of the 1/4 mile...the engine configuration is really versatile, just depends on your wallet.
George