Which Gen BBC do I have?

[mrr1999]

Hey guys-

I am about to tear into an old 454 I have laying around and I am unsure to which gen it is. (IV, V, VI). How do I identify the block I have? Thanks!

[Gordz32]

look for the casting number on the back of the block on the right side and see if there is a number and 3 letter prefix code on the left front side just in front of where the cyl. head sits and post them for everyone.

[Vegas69]

Gen V/VI have a plastic timing cover with a built in timing mark. Gen IV will have an old school small block style cover with many bolts. If the engine is out, the V/VI ahve a once piece rear seal and the IV has a 2 piece.

[mrr1999]

The timing cover has a bunch of bolts and a separate timing tab. Gen IV it is. I'll double check the #'s too. Thanks, again.

[70rs]

There also may be a casting at the back of the block inside the bolt pattern where the transmission mounts. It should have the year it was made cast in. An example would be "77 hi perf pass" or something similar.