The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Rear end question--'66 C10

I'm currently plotting a DD and had some questions about rear end gearing to suit my driving habits. Without changing the factory 250 and 4 speed transmission, how tall can I go (practically speaking) with rear end gearing?

A typical week will have me driving about 300 miles highway (60 mph), 50 miles in moderate-to-heavy in-town traffic, and about 200 miles on the Interstate. I know the Interstate travel is going to remain problematic, but I'd like to have something better for the highway driving than the 4.10 that was in my last '66.

Thanks!
Jim

If you want better RPMs on the highway, try swapping to a 3.08 rear gear. I'm assuming you don't want to change to an OD tranny.
Just for example, if you're doing 65MPH with your 4.10 gear, you might be doing 3088 RPMs. Changing the rear to 3.08 will drop you to 2320 RPMs at the same speed.
You will notice less power in the lower gears, but that's the trade off for better highway RPMs.

Thanks for the reply, Lugnutz!

Other than a shelled-out differential, the truck that prompted my question is in fair shape. I went ahead and made an offer, but even if I don't get it I think I'm going to put some more effort into locating parts for future use.