What tranny do you have, 5sp or auto? If it's a 5sp and you're gonna stay n/a, don't go any more than 4.10's, if you want to do a power adder(nitrous/forced air) then 3.73's are a good choice. I run my car at the track n/a, 4.10's are good, I'm approaching redline at the traps in 4th gear. The 4V guys can run more gear, because they can turn higher rpm's than our 2V's. If you have an auto, someone else that runs at the track might jump in here and give you some advice also.