confused - or just a stupid question

My intake is a edelbrock performer with a edelbrock 500cfm 4-barrel. The compression ration is above 9.0. My buddys Comet is a 1977 with a 302 built to pretty much stock specs. Except same intake and carb as me. His rear end is like a 2:80 or something like that. Not much different than mine. I have driven his car before and can tell it doesn't pack a punch like mine. He has only ran in the low 16's. I also noticed that my leaf springs need adjusting. I have shackels and the springs are at the bottem. They need to be raised a couple notches becasue when I take off, they bend opposite of what they should. So that probably hurts traction a lot.