OverBudget

I have a 3.36 posi rearend and I'm installing a Keisler 5 speed with a 2.87 1st gear. I want the car to be as quick as possible while not having traction problems. I had access to a 4.11 posi and thought that would be the way to go, but a couple recent responses said that traction would be a major problem and 1st gear would be too short.

Can someone give me practical advice on what the best rearend gearing would be?

Car is a 1963 roadster with a 480hp/465torque smallblock, car is 3,050lbs and will have 9.5" rear wheels with street tires.

Many many thanks in advance for your help...

jpee

I think with that kind of power your going to have traction problems with any rear you use.. Why not just leave that one in, & see how the car drives with it.. then after seeing how that one is, you can probably make a better decision.. is 5th gear an overdrive?

OverBudget

Glen: Thanks for your input.

Red96: 5th gear is an overdrive (.64).

Greybeard ZR1

It might be helpfull to start your calculations at the other end. With that 5 speed, where do you want to be, rpm wise, at cruising speed, this is obviously not a drag car, so don't make the 1/4 your priority. If you still have traction problems with your "ideal" street gear, then go to offset trailing arms and big stickies.

I'm assuming that you cruise in fifth, and run the 1/4 in fourth. That's what I do with 4.10's, and it works out well. But I have a 1.50 6th too.

Mr Mojo

In all honesty, I would stick with what you have and see how it works out.

Ironcross

Put the 4.11 in!