67Rocket

My F85 has 2:78 rear gear and with the 455 and TH 400 is responsive, would putting in a 3:08 make a noticeable difference? I am running 255 60 15 tires. Thanks

steverw

Yes is my answer. I did the same thing with my 73 Trans Am. Someone had put in a similarly geared single trac camero rear end, and with its 455 it wasnt bad. I put in a 3.08 posi and IMO it made a big, but nice, and still very streetable difference.

joe_padavano

I'd go at least 3.23 with those tall tires.

oldcutlass

I agree with Joe, it'll make the big fun pedal way more fun.

marxjunk

i doubt you would know the diff unlessit was a posi..too close..

3.23...3.42...youd know it...

67Rocket

I have been considering a 3:23 but they are hard to find. The guys in Oregon only do 3:55, any suggestions? Thanks

marxjunk

lots of pontiacs had 3.23s

3.55s with really tall tires wouldnt be bad...lots of fun..

Magna86

I went from 2.56 open to 3.08 posi in my 71 with the 455 and TH350. Made a difference and is a pleasure to drive. Do it

marxjunk

2.56 to 3.08..you will feel it...it wont be huge but you will know..

2.78 to 3.08..there isnt a big enough gap to know..it may be faster..but you wont really feel it..the gear ratio is too close..