The Money Pit

I just put in the BowTie 700r4 trans,and though the difference is like night and day on the highway,I'm not convinced the speedometr is correct.I found a chart posted by one of the forum members that shows tire size/gears VS. MPH. According to the chart at 2500 in overdrive I should be at 77 mph,where mine shows 64 mph.Gas mileage is also not as good as expected,so I think the speedometer gears are the wrong ones.

Does anyone know which speedometer gears to use with a 3.70 rear,and 26.7" tires?Been on three or four sites with different info so far. :crazy:

norvalwilhelm

I don't know which speedometer gear you need but with my 700 and 4.11 gears at 60 I reved 2200 and at 70 2500. You are definitely out alot. I believe the 77 mph at 2500 with 3.73.

HWY 9 - Z06

I just got done doing the same thing and didnt find much in the way of helpful calculators on the internet. but what i did learn was you need to determine how much you are off. having someone with a known accurate speedo pacing me and calling off speeds on the cell phone helped me, because they dont have the speedometer checks set up on the highways around here anymore. then count the teeth on your speedo gear. the formula equates to 1 tooth = 3 mph. that is 1 tooth more=3 mph slower, vs. 1 tooth less = 3 miles per hour faster. i am not having success in copying and pasting the chart i have listing all the gears and part numbers, but i not only had to change gears i had to change sleeves, as one sleeve is for 40 teeth and above and the other sleeve is for 39 teeth and below.