Surprisingly big difference running 2400-2700. Keep in mind that is a 12.5% increase. Also remember is stock form you are turning closer to 2k@75. Also what OD ratio are those numbers assuming? .70?

 

Yes the website has it set at .70

 

I had my truck on 31's with 4.56's for a little while and it was a nice combo, IMO. Since your tires are shorter, i'd say go with 4.30's.

Highway cruising is nice when you have a little extra gear. You maintain speed easier, and the trans does less downshifting. But, I'm also the kind of guy that doesn't give two ***** about fuel mileage...

 

Seems like it might be 4.30s then. I was looking for Yukon of USA standard but cant find them on rons website nor summit.

 

I think Motive Gear may be one of the only companies that makes 4.30's.

 

http://m.summitracing.com/search/dep...n-ratio/4-30-1

 

i have 4.10s with a 6 speed and converter. She likes to drink gas in town, i don't DD it tho so its whatever. I run at 2100 at 70mph I believe with a 31" tire. I would have gone 4.30 but didnt have the option for the 14 bolt rear and wanted to keep the RPMs down on the highway so i stayed away from 4.56. Gears make a nice difference going from 3.42s to 4.10s.

 

This is were im at with 3.73.