For those of you who were curious, there was a difference in the 302 blocks. A 1/16 inch difference. Enough that I couldnt get the coupler aligned. I put a 1/16 inch washer under both rear mounts and whalaa! So D4DE-6015-BA is different than D4DE-6015-AA. Guess in a car it wouldnt matter. Thanks for your help on the matter. Gonna taker out and stir up the lake.