The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 61 Apache Differential Swap

I'm thinking about buying a 61 Apache with a 350 crate motor and a 4 speed.
The truck is geared VERY low, too low to drive on the highway. I don't want to change the differential in the axle - I would change the whole axle as an assembly. Does anyone know what axles from other vehicles will fit? What are my options?

I'm sure others will chime in and suggest that changing the gears is the easiest way. Welcome to the bolt.

Looks like about $350 for parts to change gears. How hard is it to get the shims etc. set up correctly?

might want to repost your question in THE CRASH BOX forum or maybe the mods will move this one there for you.

What size truck is it? 1/2, 3/4 or 1 ton? That will make a difference as to what can be done and possibly what gears are actually in the rearend. Generally speaking, a '61 has 3.90 in 1/2 tons, 4.56 in 3/4 tons, and 5.13 in 1 tons. Thae only avaiable aftermarket gears for that year truck are 3.38 for the 1/2 tons.

Hi, R

Ditto what Longbox just posted. My '61 is a 3/4 ton and has the 4.56 gears. I completely hear you on the "geared low" thing. Oh, mine is a Detroit locker, too. Anyhow, when I called around I was told that the only gears I could buy for mine was exactly what I have.

So, I'm also curious what others post, as eventually I will be looking into changing out rear-ends on my truck, as well.

On my C20 (4.57 rear), the cheapest, best bang for the buck was putting in a WC T5 transmission with .63 OD. I did that when I was in San Diego which is nothing BUT freeways. The one I found came out of a '88 Z28. Most people change out the tail housing on these with one from an S10 so the shifter is closer to the same spot on the floor. Lots of information here and all over the interweb about this.

You might want to find out what gears it now has. If it was a hot rod it may have 4:56 gears, in which case a 3:08 would make a difference.

Most of the time it is in the transmission with a 1 to 1 for the top gear. Without overdrive, all old trucks were geared low.

In the tech section there is a link to figure final speeds based on tire diameter and gears. I changed the xls worksheet to add for an overdrive in the tranny.
There are a number of websites that give the diameter of different tire sizes, and their RPM ie mine equals 29.9" and 791 revolutions per mile. That way you know exactly what tranny, rear gears and tires give what speed at a given engine RPM.