here is the link for that one.Do a search on 'ratios' and you'll see the topic discussed by 'croz98gt'. He shows you the different speeds at different RPMs for the 3.73, 4.10 and 4.56 gears.
I do have 373's already and I did have the car on the track last year . The hP at the time was 556 rwhp. I found it difficult to get the power to the ground comming out of the turns even in 3rd gear. After that experience I too had thoughts of going back to the 331's. With the flat torque #'s this engine produces esp with the kind of hp #'s I will be getting with the stage 3 TVS ( 680rwhp) 331's would be better suited for the open track IMO also.Sprint and I were just talking about this svtbird, this might be timely since installing your TVS. Have you done the gear swap yet? If not, you might want to wait to get on the track before switching gears, 3.73's might be too much for the track with the RWHP you're putting down now? Anyway, as I said above, Sprint PMed me about gears and the following was my reply,
"I'm running 3.73's which were great with about 550-560 rwhp but since I went up to 610 rwhp the 3.73's are a little too much especially coming out of turns in second gear, the tires will spin if you get on it too quickly; it's managable but you can't go to WOT after the apex of a turn and ride it through to the straight which I was able to do on most turns in second when it was 559 rwhp with 3.73's.
With the mods that you are planning, "93 octane tune but will be adding a pulley & CAI ", you should get up to the 550-560 rwhp level and at this level, as I said above, I think the 3.73's are a very good choice. Are you considering upgrading the heat exchanger? I think this a great mod for a street/track car, it doesn't add HP but it keeps you from loosing HP due to heat soak and we both know how hot it gets on the track in the summer time.
I've been waiting for the 2.9 Whipple super charger to become available which will take me to my 670-680 rwhp goal, I will probably go down to 3.50's or back to the stock 3.31's to help keep the tires from spinning with the higher HP; I'll also be looking at changing the differental and axles next time around as well.
Hope that helps,