[DanEC]

Even with a wide ratio Toploader, I think a 2.88 rear is going to be an issue. To get to 500 HP you are going to need at least a 235 to 240 duration cam and IMO you are going to have problems with starts. It will manage it with careful, slow starts and some clutch slipping, but I'm pretty sure neither you or your car will be happy. I have heard of good results with a 3.07 and WR Toploader although a 3.31 and WR Toploader is more commonly used. Additionally, the higher speed you go with the rear end, the greater the rpm drop between gears is going to be. Shifting at moderate rpm to the next gear is going to result in a big drop in revs. Based on your desire for a high speed rear and the ability to do battle in the hills and twistys, a 5 speed may be a better match for you.