I'm current running a 3.73 with a 26" tall tire and it rips pretty good. I'd bet a 3.27 or 3.55 would probably be best as I can destroy the 315/30/18 Hoosier drag radials from a 3rd gear roll once boost comes on (haven't tried brake boosting yet). 18 psi from a 7175 precision turbo shoving air into a little 4.6L will do that though.
3.55's may be a good choice as long as you can keep your foot planted and the tires hooking. 3.73's would most likely ensure crossing the traps (1/4 mi) closer to my peak HP but, I think 3.27's will be overall better for a mostly street driven turbo car. I'll let you know first hand soon.
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more!