??????

I didn't want to break in on the thread that dusmon started, but now I'm confused. When you guys are talking about tire size, rpm and gear ratio combo, I don't follow. The math that I'm using is rpm x tire dia. and mph x 336. Then you divide the two and it comes up with the gear ratio required. With the combo I have I need a 530 to be at 7200 at the traps. Please enlighten me.