I bought a 02 c5 in july. and ordered an ati procharger stage two. It should be here by thursday. I just dont know what gears and stall will work best for my needs..I am looking to get the car to low 11s but also drive it on the weekends. now it has 273. thank you

 

Well, most people advise to increase the numerical ratio of the rear end (i.le., from 2.73 to 3.23 or . . .) for performance.
But, I have an ATI Procharger on my car (and extra cubes), too, and I'm not convinced. I stuck with my stock ratio after seeing how it performed with the extra power.

So I'd wait and get the engine sorted out and see what you do with the stock axle ratio. You can always change it later. But It can get tiresome running around all day with the engine reving higher because of an higher numerical ratio.