Yes and no, all will physically bolt on, but a AVS block will have the top and bottom of the pan not touching the block if you put a earlier 31 on it (they are rare but out there). I told how to put a 28 crank in a 31 AVS some years ago, this gives you a larger cam gear that is not as prone to breakage as the thinner AVS. You basically add metal to the either the pan or the block to seal the sump, but beware, aluminun soaks up oil and is very hard to weld, i sealed the porisity with sealant and had no leaks.
