I want to keep my family’s pickup “original/custom”

Question:

I’m in the process of restoring a 1949 Chevrolet 3100 pickup that has been in my family since 1949.

I’m using a restoration company (GForce Design Concepts) here in Chambersburg, Pennsylvania, to do all the bodywork, painting and some mechanical. I will be doing the remaining mechanical and electrical.

Restoration will be mostly original except the 216 six-cylinder engine will be replaced with a small block Chevy 350 and a turbo 350 automatic transmission. This is where my problem arises, since I want to keep the rest of the truck as original as possible even if it will now become a “custom pickup.”

In this regard I would like to keep the original rear axle and differential, so I can keep the original 16” wheels on the truck. The gear ratio will be changed from 4.11:1 to 3.55 by replacing the ring and pinion gears, which are available.

My problem, obviously, is the drive shaft. Is there a known method to connect the original tube drive shaft to the Turbo 350 automatic transmission?

Or, conversely, is there a way to connect a modern drive shaft to the original rear end?

A second problem is created by my wanting to keep the original steering column and column shift, while using the newer Turbo 350 transmission. We think we know how to do it, but perhaps someone already has and we can use that method.

Incidentally, the truck was used in my Dad’s Skelly Service Station in Garnett, Kansas, back in the 1950s and ’60s.

I have a 35mm color picture of it taken in 1950 with my dad and myself standing behind it and in front of a Skelly Chevrolet tank truck at the side of the Skelly Station. We had just driven both in the 4th of July parade in Garnett.

The plan is to complete the restoration with the original lettering, which includes the Skelly emblem, Hood Tires, Harper’s Service, Garnett, KS, and Phone no. 234.

Answer:

It’s really wonderful that you still have the truck that your dad bought new. It’s a family heirloom that you can use and enjoy constantly!

As far as I understand, you cannot retain the original torque tube “closed” rear end arrangement if you’re going to install a TH350 transmission. You don’t have to replace the entire axle assembly but that may be the easiest and least expensive route to take. You can remove the original center section and torque tube assembly and replace it with a later “open” center section. Chevrolet began using open center sections in trucks beginning in 1955. If you do this then you will need to have a suitably sized driveshaft made to connect the new center section to the new TH350. You’ll also need to address the pivots on your original rear springs.

Without the additional support of the torque tube the rear axle housing will pivot and cause various problems, including a severe pinion angle that can break the U-joint.

The easiest way to fix the pivoting axle housing issue is with a kit designed for the purpose. Variousvendors, including Classic Performance Products (classicperform.com) sell such a kit.

I don’t know of an off-the-shelf solution to your transmission linkage problem. Many GM vehicles, including, of course, pickup trucks, came with column shifted TH350 transmissions and I would start by pirating the whole shifter/linkage setup off of an older pickup truck and modifying it as needed to work on your truck. This will require some fabrication and welding skills but with patience and careful thought you can likely handle it.