Rear end gear options with stock axle
 

Ok I'm a new member, luckily Im getting to know this truck inside and out, since its a rolling resto. From the threads I've read sofar it looks like my standard gears should be 3.90. This is also pretty obvious since at 55 it feels like the engine is close to redline. My tires are stock size, 28"diameter. I ran the calculators on Richmond's site and determined best ratio to be able to do 75 comfortably would be 2.73. I'm looking to NOT spend a small fortune on this and keeping the Muncie 3spd HD because of the rarity and cool factor of it. How can I make this work with my existing axle or do I really need to swap out the whole darn rear end?

Re: Rear end gear options with stock axle
 

If this is your '62 GMC, and if it has the Eaton HO32, then there is only one other gear available for those. They are aftermarket 3.38 gears, and are a bit spendy when you can find them. If your truck has the Dana 44, then there are quite a few options, but none higher than 3.54 that I am aware of. Otherwise you will have to change to a different differential. Also, changing to a very high rear gear doesn't always mean better mpg's. IMO, 2.73 gears with a 3 speed won't be a very good combo, other than on the highway.

Re: Rear end gear options with stock axle
 

yeah I had seen info about the 3.38s being one of few options. I'm more concerned about the redline on my d motor being 3900 rpm and the fact that everyone in az drives 75 so I need to be be able to keep up. The muncie I put in is a 3:1 1st, 2.85 2nd and 1:1 3rd.