My 70's were 3 Camaros and 4 corvettes. Young and single, lol. Motors back then being all mechanical and no ECU help, could be of the same displacement, but camshafts and lifters varied. A 70 Vette motor, which I later bought and put in a '71 Camaro, could be had with a hydraulic cam or a solid lifter cam. Could be as much as 30 hp difference with the cam alone, same motor. In fact, the short block I bought had the solid, and I changed out to a more aggressive hydraulic. Less I had to do to adjust the valves that way. Those were some fun days of experimentation of gaining hp. Today, you let a computer do it for the most part. Go figure. Well, I better add, I know it isn't quite that simple.
As for wheels, just remember the wheels sensors, deviate too much, and you are in limp mode. The puter knows better. I run 17" wheels and drag radials which are the same height as an 18" wheel and tire or close to it. Those who experimented with wheels sizes didn't find much of anything as Jim can attest to...