I don't know if this is the correct forum for my question, but I think I will at least get headed in the right direction.
I have a 38 gmc 1/2 ton with a long bed. I have been thinking about turning it into a 4x4, not sure what to use for the 4x4 conversion. I have thought about an s10 4x4 and modifing the s10 frame, I know the rear axle will work on my 38 width wise. I have also thought about just using a regular full size 4x4 and manufacturer what parts I would need. Anyway I thought I would ask you guys, and if you did not know, you could point me in the right direction to find the answers to my question.
It really depends on what kind of modifications you are willing to do.
Doing an axle swap from something like a CJ5 or an S10 is a lot less work than doing a full frame swap. An axle swap will require modifications to the brakes to make them work with the disks (or disk/drum) setup on the axles. You will also have to figure out how to connect the steering because the steering box is mounted in an unusual location on the older trucks. Doing an axle swap will not generally require any permanent mods to the truck if someone wants to be able to reverse it later. Make sure you track what vehicle your various parts came off for when you need to replace them later.
A frame swap will have a complete set of matched running gear and you will benefit from 50+ years of technological advancement, but it will be a different kind of work (and more of it) to move the body over and deal with replumbing the fuel system and such.
Likely it's a 3/4 ton if it has a long bed. 1/2 tons were all short beds. Could be a mishmash of stuff to get a 1/2 ton long bed. Axle width should be priority, to wide and they look really goofy.
Joe my gmc is a 1/2 not a 3/4 i have seen a bunch of gmc 1/2 that are long bed
I was thinking finding a donor s10 truck that was complete. S10s 4x4 frame are a little wider in front and about the same in the rear. Dumb [censored] me had a complete s10 truck but had to get rid of it do to a move. It would be easy( for me) to modify the s10 frame for the 38 frame to fit. Some of this is self dought, I have not done any kind of automotive or body work in probably 10 years because of work, I am retired now so I have plenty of time. I have experience in fabricating parts and modifications, been around the automotive industry for 50 years because of my step dad( he was an automotive machinest). Plus was also looking for opinions and guidance
This front 47.1 GMC frame shows the problem encountered with front section of 2wd frames that do not have enough clearance for a front 4wd axle. The problem is solved by raising the frame higher above the axle for clearance, which may not be desirable for handling on the road.
One must determine whether raising the frame for adequate clearance or putting some 4wd frame under an older 2wd truck is less work.
The difference, of course, is in the factory dropped axle as demonstrated in this 55.2 two ton.
Ed
Last edited by EdPruss; 05/14/202212:32 PM.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
I decided to use an '88 GMC k2500 for my 4x4 conversion. The gas tank was outside the frame before '88, so that was one thing to consider. '88 and later had the primary gas tank on the driver side and the secondary in the rear, I moved the filler to the driver side, but I think it would have been easy enough to move the tank to the passenger side. I was able to get the ride height the same as original and the tires are not outside of the fenders so I'm happy about that. I'm not sure how the width compares between '38 and '47.2 though.
