Due to a different bolt pattern on the buick transmission, a chevy engine would not be compatible. But Summit Racing and I am sure other aftermarket parts dealers have an adapter plate that would allow such a swap to occur. Not sure the part number.

I am pretty sure it wouldnt bolt up to your Transmission that is if you do have a chevrolet transmission. had same issue with an Oldsmobile .. different bell housing on chev pontiac to buick oldsmobile but all gm cars have the ability to be adjusted to modification such as the bolt pattern of engine mounts