A 3800 motor from a 1998 GT is replacing the 3800 motor in a 2001 GT ... Mechanic is saying that the motor from the 1997 sets 3" farther ahead then the 2001 motor and that new mounts have to be made to make it line up. Everything I've read online and also in the GM shop manuals indicates nothing about a location or size difference. Can anyone tell me if what he is saying is true or is he just putting me off... He's had the car for several weeks and keeps coming up with one excuse after another on why it's not done yet........