3:90 or 4:10's I think I heard that the 1st gear is shorter compared to the 60. So would 3:90's be better. I plan on doing a 3400 stall when I put the tranny in.

 

My HD came with 4.10s stock and I love them... well not the gas mileage, but nothing can beat the looks you get powersliding a 6000+ pound truck through an intersection

 

I am running a 28.5" tall tire. I am sure your tire is a little taller.

 

I think I might go with 4:10's since I run 20's on the street.

 

I have the 80e, 31.22 is my outside diameter and I am running 4.10's with a 2800 stall. I love them. If I had to do it over again...hmmm...I might of went with 3.9's, what are you upgrading from? 3.73...then goto to the 4.10. 3.4's then goto 3.9. Just my 2cents. 28.5 might make those 4.10's awefully "revvy". I always hated the gear picking thing...it's all about what you like...good luck nevertheless and let us know which you end up with and how you like them.

 

I beleive my tire is also 31.22 they are 285/50/20 anyway my 3.90s are perfect for my liking.

 

i think its like 245/75-16 or somthin...stock, well the fronts are stock, but Im on my 3rd set of rear tires, some how they go bald really quick, and shes only 9mo old.

 

I guess since I am on 20's and like my ***** to the walls, I will go with 4:10's
Thanks for the help.

 

I did some research and here is what I found.
6000 rpm redline, 28.5 dia. tire, with tranny ratios at 2.48 for 1st, 1.48 for 2nd and 1 for 3rd

These are the speed at the shift point at redline
------ 1st - 2nd - 3rd

3.90 - 52.78 - 88 - 130

4.10 - 50 - 83.6 - 123

4.56 - 44.98 - 75.38 - 111.56

I might do 4.56 gear, but this will greatly reduce my top speed. I think 4.10 are just going to make up for the swap.

 

Be careful, the pinion gear gets small the numerically higher the gear and the 10bolt isnt the strongest rear end to have any way.