The Stovebolt Site Forums The Shop Area The HiPo Shop Task Force 3800 to 3100 conversion

I've been collecting TF parts to build a work truck. My wife calls it my Johnny Cash truck because it will be assembled with parts from so many different years.

I want to use 1/2 ton axles so that I can use 3.55 gears on the rear end and so that I don't have to struggle with the limitations of tire sizes on the factory 8 lug rims. I have a nice set of 16" rims with original hubcaps off a '57 3100 that I want to use. I also have the front and rear axles, springs and steering components off the same truck.

The truck will be a short bed, but I have the opportunity to pick up either a 3800 or 3600 rolling chassis. I can shorten either frame to make it a short bed.

I'm have a few questions that I'm hoping someone can help me with.

Will 3100 springs directly bolt into a 3600 or 3800 frame? Front and rear?

If the springs aren't a direct bolt-in, are the 3100 axles a direct bolt-in on either the 3600 or 3800 springs? Front and rear?

Are the steering components interchangeable on all of the models?

Thanks for your help,

Matt

I think the 3800 springs are wider than 3100. I don't know about 3600. This link may have some helpful info. https://dl.dropboxusercontent.com/u/30524403/1957-3800-rear-springs.pdf

FF and SF GM 14 bolt axles come with lots of ratios, including 3.73, come with 8 on 6.5"(FF) and 6 on 5.5"(SF), disc brakes with park brake available. Several widths. Lots available in yards. Another option.

Ed

If I'm not mistaken i believe the distance from leaf spring eye to eye is different on the 3800 springs so I don't think they would simply bolt in,

3800's have straight frame rails behind the cab. Installing 1/2 ton running gear will dramatically alter the angle of the frame rails and result in totally different handling and steering characteristics. I can't think of much of anything that would be a direct bolt-in swap. Even if you get the axles to fit, the bed won't, no matter how you alter the wheelbase. The world will just have another butchered-up, unfinished project rusting away in the weeds.
Jerry

You can make a 3600 or 3800 truck just as driveable and perhaps more useful than a 3100.

There are similar upgrades and swaps for the bigger trucks just like the small ones, much discussion already on the forum. Check out the Tons of fun section.

Usually a better plan to stick reasonably close to the model truck you have, don't try to make it into something it isn't.

Grigg

Guys, all good thoughts. You backed up what I was already thinking. Glad I put the idea out there for some input.

Matt

Here's a trashed-out 3800 I quit driving when the cab got so rusty the doors were threatening to fall off from the deteriorated hinge pockets. I sold a bunch of parts off it and finally traded the rolling chassis to someone for a 261 engine.

http://www.hunt101.com/data/500/1068959_3800_003.jpg

Some guys' trash is another's treasure- - - -that one was just too far gone for me to consider putting back on the road!
Jerry

Another thought, if you really want a 1/2 ton, look for a junk 3100 with a good frame and move your sheetmetal and driveline over to it. In the long run it will be cheaper and everything will line up and bolt up...then sell your rolling 3800 chassis to recope some of your costs.

Mike B

Well, I'll stick to a half ton frame. That was my original plan until I had the option to pick up either the 3600 or 3800 rolling chassis for peanuts. Sometimes free isn't free.

Matt