I believe I have a 71 455 with Ga heads. (the heads were swapped)
Just curious what compression ratio I would have. Thanks!

 

All BBO heads have about the same size chambers except for the D heads. CR was varied by changing the size of the piston dish. All 1971 motors were low compression (8.5:1 or 9:1).

 

not enough information. was the motor rebuild or not? need things like head gasket thickness, head cc (especially if heads were shaved), block zero decked or pistons in the hole? I could guess that it's anywhere from 8:1 to 11:1 but thats a big ballpark not knowing anything about your engine

 

100% stock.
back of the distributor is number 71
also found a 396021F
back by the flexplate is F4
Ga Heads (he said those were swapped out)