A little bit, not much though. I'm 6'3" 240lbs and I fit comfortably. I was a bit of an idiot when it came to fiberglass at that time, looking back I would have done it in glass and not had to move my seat at all....but at the time I made it out of 1/2" MDF, so the box was WAAAAAAAAAAAAAAAY bigger than it needed to be

Yeah, if you have the bench seat you don't have to worry about the fancy amp rack like I did....it was just for show anyway