Sounds like you have the right idea. The four bolt pattern ones (for the six cylinder cars) are a different rear from the 8" (for V8's) the guys have been talking about. While the 8" could be a bolt in, if you found the correct one, you would also have to change wheels. If it's just for stock, staying with the four bolt would probably be better. The only other thing to consider is the gear ratio. If his is a stick, you should try to get a rear from a stick equipped car, and vice versa.