Bellhousing bolt pattern

[theo]

I'm looking at a secondhand "AA" code tranny (presently fitted to an 83 caddy engine) with a view to rebuilding it and fitting behind my 80 vette's 350 motor.
Details about that are here

The thing is, I obviously need to be sure it'll fit on the chev engine. I'm awaiting photos from the seller, which I hope will help, but in the mean time, can anyone suggest whether this one will have the universal bolt pattern or not?

Is there a rule of thumb as to which 200-4rs actually had the universal pattern and which had the B-O-P pattern?
There are apparently "spare" bolt holes in the bellhousing.. is this a sure sign that it's universal?


thanks!

Theo

 

[77 cruiser]

If it has a dual pattern it is a BOP & Chev. Read the rest you should be OK.

 

[bison]

If it has a dual pattern it is a BOP & Chev. Read the rest you should be OK.

Exactly. If its a single patten then its a no go on a Chevy.

 

[GNeric]

I have seen only 1 Chevy only pattern 200-4R and 2 BOP only patterns. They seem to be the early date codes 80-81 years for the BOP and pre 84 for the Chevy. Caddy I would think would be the UniBell housing. Can't say for 100% sure.