There is alot on this subject. Probably a good page's worth and im tired... unless your in for building one or have a DSM.

4g64s were all SOHC motors except a 1994 Galant model which was DOHC, which people are coping the setup and making the motor turbo friendly, and putting them in place of 2.0L

think Chevy.... joe smoe has a 87 Camaro with a 305.... he wants a 350... motor is the same size physically, just the 350 is bigger and more power. same concept.