3/4 Ton Conversion

[69 C10 LWB]

Im currently on the hunt for a new truck and so far I havent had much luck finding what I want. When I was in school I had a 64 C20 and that was my favorite truck ever. I have been looking at C20s and C30s and all the ones I have looked at have been solid gold and out of my price range or so far gone Im amazed the duct tape is still able to hold the cab on.

I currently have a 1973 GMC 2500 with a good drivetrain. My plan was to strip this truck down so I would have disc brakes and possibly a V8.

Here is my question. I have a line on a 64 C10 shortbed that has been sitting. What is the difference between C10 and C20 frames? Is there any reason I cant take my front suspension and drivetrain and convert to 3/4 ton? I know most people go the other way but I like to be able to use my trucks as a truck if needed. I know I will have to change the perches on the axle but that would be easy. Anything other than stiffer springs and different axle out back?

[Short 3/4]

Originally Posted by 69 C10 LWB

Im currently on the hunt for a new truck and so far I havent had much luck finding what I want. When I was in school I had a 64 C20 and that was my favorite truck ever. I have been looking at C20s and C30s and all the ones I have looked at have been solid gold and out of my price range or so far gone Im amazed the duct tape is still able to hold the cab on.

I currently have a 1973 GMC 2500 with a good drivetrain. My plan was to strip this truck down so I would have disc brakes and possibly a V8.

Here is my question. I have a line on a 64 C10 shortbed that has been sitting. What is the difference between C10 and C20 frames? Is there any reason I cant take my front suspension and drivetrain and convert to 3/4 ton? I know most people go the other way but I like to be able to use my trucks as a truck if needed. I know I will have to change the perches on the axle but that would be easy. Anything other than stiffer springs and different axle out back?

I did this on a 66 and it was a great truck that served me very well for over 30 years. I would still be driving it but the rust monster finally ate it. I liked the size of the shortbed but could easily and safely carry a cord of wood or a yard of gravel.
The 3/4 ton front brakes and suspension are a bolt on and work very well. As you said, the rear is just moving the spring perches. You will have to redo the drive shaft, but any good driveshaft shop can do that. Also will want an adjustable brake proportioning valve.Finally you should box in your rear trailing arms, as they can crack under heavy load.
You will have a very useful and unique truck when done.
Good luck, Tom

[Short 3/4]

Forgot to mention. For springs I used aftermarket ( Moog I think) Progressive HD 3/4 ton replacement coil units, both front and rear, and the ride was very good both empty and loaded.
Tom

[Captainfab]

The C20 frames are just slightly thicker steel, the trailing arms have extra reinforcements and the trailing arm crossmember has angled braces forward to the frame rails. Oh and the different rear cab mounts. Otherwise pretty much the same. If you need trailing arm mounts for the 14 bolt, let me know, I make those as well.

[franken]

One thing to remember is there never were any 3/4 ton shortbeds.

[s10blaster]

Thats interesting you want to convert to a c20 (from a c10)...I've come across a couple 64 c20 trucks whilst searching for a c10...and they seem pretty good but I don't want a c20.
I love the information this forum shares ...really enjoying learning so much about these awesome trucks.

[Bentbolt]

I'm in southern Iowa and swapping my c20 in to a c10. I'm pulling out the rear axle, arms and crossmember. And the front also soon. It has all new brakes.

[rideblue00]

Do you have pics of your truck Short 3/4?

[350TacoZilla]

Unless you are planning to go lowered why not plunk the 64 body on the 73 frame? get the newer suspension/brakes/steering and the 3/4 ton long bed frame, sell the short bed and put long bed on it. I would bet there are people out there that would trade a long bed for short and even throw few bucks your way not to mention selling the C10 frame then. Its a pity you dont live close to me since I have a 63 3/4ton I'll be pulling the body off of this spring.

[Captainfab]

Putting a '60-'66 body onto a '73-'87 frame is a LOT of work for really no gain. In reality the trailing arm, coil spring rear suspension is superior to the leaf springs used in the '73+. Plus then you have possible legal issues with the frame and cab VIN's not matching. This frame swap has been discussed many, many, many times here on the forum.

Originally Posted by 350TacoZilla

Unless you are planning to go lowered why not plunk the 64 body on the 73 frame? get the newer suspension/brakes/steering and the 3/4 ton long bed frame, sell the short bed and put long bed on it. I would bet there are people out there that would trade a long bed for short and even throw few bucks your way not to mention selling the C10 frame then. Its a pity you dont live close to me since I have a 63 3/4ton I'll be pulling the body off of this spring.

[Short 3/4]

Originally Posted by rideblue00

Do you have pics of your truck Short 3/4?

Sorry, no. All I have are some old print pictures that I don't have the equipment or skill to post ( like I said the truck is no longer with us). Ironically I know there are lots of pictures of that truck out there because every time my wife would strap her longboard on the lumber rack and head up the coast, the tourists on Hiway 1 would go nuts and hang out their windows to get a picture of the cute blond in the rusty old truck headed out to catch some waves. Sure miss that truck, thank God I still have the wife.
Tom

[Short 3/4]

Originally Posted by franken

One thing to remember is there never were any 3/4 ton shortbeds.

Which is what makes them fun. I have built both of mine as stock looking as possible. I like seeing people scratch their heads trying to figure out what they're looking at. BTW Dodge and International did make short 3/4's. My old short 3/4 Power Wagon is what got me hooked on them

[350TacoZilla]

Originally Posted by Captainfab

Putting a '60-'66 body onto a '73-'87 frame is a LOT of work for really no gain. In reality the trailing arm, coil spring rear suspension is superior to the leaf springs used in the '73+. Plus then you have possible legal issues with the frame and cab VIN's not matching. This frame swap has been discussed many, many, many times here on the forum.

For me if its 3/4T and going to be used as a truck it should be
1.long bed
2.leaf sprung

I guess if its just going to be a driver/show piece short bed/coil is fine.Again this is personal opinions so they are going to differ but I also would never own a truck that you cant use as a truck. I also dont see making 6 new cab supports as more work than swapping the entire front suspension/crossmember over, cutting leaf mounts off the rear and setting up the trailing arm mounts on the 3/4T axle along with all the miscellaneous stuff that goes with that like brakes/steering etc.

For legal issues all I have to do is contact state police and have them verify both starting vehicles are not stolen, do the swap and then let them do a safety inspection on the truck. Costs tiny bit more than the normal inspection and titling process but you can also get the payload/towing upped to the newer 3/4T chassis rating not stuck with the 1/2 rating.

[Captainfab]

We can agree to disagree. I've done the body/frame swap......never again.