33delivery, what is your idea for the car? The 700r4 has a 3.08:1 1st gear, you are gonna ROAST the hides at every light with a 31.5 inch tire. Besides the concept of overdrive is to lower engine RPM on the freeway. 2200 revs at 65 is quite a bit these days. I realize it's a hot rod with a hot motor. Just some perspective, my wifes car a stock 95z-28, 275 horse with a t-56 trans. The motor runs about 1700 at 65, just loping along. I'm not exactly sure but, I believe a 3.50 gear with a 30 inch tire and a 3.08 1st gear wil be like a 4.11 overall gear. Anyway I just wanted to give you a little more info. Oh yeah, I didn't use any calculators for that just off the cuff from building my car. I'm runnning a blown 406 w/700r4 w/29.5 inch tire and 3.00 & 3.50 rear gears. I like the 3.50's the best, but I like low rev's on the hiway! Good Luck...