3:55 is a great gear, but you need a 700R4 tranny that includes an 28% overdrive. Everything else is a compromise. Our FB with 3:55s and a 400 turbo was great around town but wanted to overheat and was very loud at cruise. Replaced the 400 turbo with a 700r4, kept the 3:55 and now have an essentially a 4:20 rear gear in 1st, and a 2:73 in fourth gear. Works great! There is a reason GM went to it, direct bolt in with the right parts.