If I were a betting man, I'd bet you have 2.9sumpins in a 7.25 rear. If drag racing is your bag, I would jump a full ratio to see a real difference. I wouldn't waste my time going less than 3.91's. I've changed 1/4 to 1/2 ratio, and it's just too small of a change. Going in your case from say 2.9's, to 3.23's or 3.55's just isn't worth it.
