engine mounts not lining up

I have a 84 trans am I am turning into a hot rod
I have a 350 engine out of a 80 chevy truck that I am trying to put in the TA. I am using the original motor mounts from the 305 out of the TA. (part numbers 334971 & 039436)The problem is the mounts on the engine will not line up with the crossmember mounts. I get one through bolt in and the other bolt hole does not line up its the width of the hole off.
Any one have any ideas? I have swaped mounts from side to side (no change) double checked mounts on the frame (they only go on one way)
I am at a lost so any help would be great.