C10 to C20 conversion

[DreamRyder1963]

Recently my buddy and I picked up a 1969 c10 longbed for $400. The bed and most of the cab is shot but it runs and does have some nice parts left intact. One of the main reasons we bought it is because he was looking for a truck he could use as a farm truck and not care if it gets dented and beat up. He has bought a flat bed to replace whats left of the 8 foot box and we would like to increase the hauling capacity of the truck. He is wanting to make it effectly a C20. Beyond swapping the leaf springs, what else do we need to do?

[hugger6933]

the front suspension is different as in heavier but the upper and lower control arms would change on to the 1/2 ton frame. the rear is different as well, but if just needing a little bit heavier truck he could maybe just use some 3/4 ton springs to stiffin up the truck a little bit. I grew up on the farm and as a farm boy that is the way it would be done but now as a truck rebuilder I'd opt for the former[cause there is resale for me to think about]. Jim

[DreamRyder1963]

Our goal is mainly to be able to haul heavier loads around the farm. I don't believe we need to upgrade the front suspension for our purpose. Resale value definitely not an issue the truck is pretty beat up. Are the rearends the same?

[hugger6933]

No the rear ends are different as well as most of the suspension. The later trucks like the 88-98 body style had two different 3/4 tons and they had rears that were same in some 1/2 ton and 3/4 cases because the GVW rating was for the 1/2 ton like 5600 or 6200 depending on spring package, and the 6 lug 3/4 ton was a 7200 GVW and the 8 lug[ had a option c6p] it was an 8600 GVW.The trucks back in the day didn't offer as many choices as they do now in suspensions and ride as it wasn't a big selling point then.

[SS Tim]

Not many choices, really?
A 69 C20 could have a H052 or a Dana 60 rear end depending on engine and transmission selected.
The standard rear suspension was coils with HD coils plus optional half leaf auxiliary springs with either.
The optional leaf springs were offered as well as were HD rear leaf springs and full leaf auxiliary springs.

Upgrading a truck is more than just a matter of springs.
The frame is always a first consideration.
Roughly put the C20 frame is ~25% heavier than a C10s.
The coil C20 frame used extra braces and reinforced rear control arms too.
Axles should be upgraded to the full floater style anytime high or excessive shock loads are present (look to all the 8-lug Blazers out there, its for a reason).
Finally there are brake concerns.
Of course all of these are relative to use. Driving down a dirt road at 10mph is very different from running a loaded truck to town or back with as much hay as you can get away with.
Licensed max weight is something to consider as well.
C10s are by and large light duty trucks. Some were sprung as low as 4400 lb GVW. Depending on the actual curb weight that put some trucks below a 1000 lb load in the bed. Plus that was best case with three 150lb people and no options.

[DreamRyder1963]

I see us using this hauling wood, concrete, and other farm supplies up and down his dirt road. It may see the occasional trip to tractor supply. Is there any benefit to swapping to the C20 springs alone or would we be wasting our time without upgrading the entire frame? Here is the truck as it currently sits. It is a 327 with an auto transmission. Hopefully the beds will be swapped soon.

[1971 cheburban]

well if you need lower control arms and hub, spindle and brake assembly I have both sides for sale in good shape

[Zable49]

Ok, I have to give my two cents (this is from an old farm hand). Since your friend will be staying on the farm and not driving it on the highway I would do two things.

First off, I would start looking for a 3/4 or even 1 ton pickup that you could use later down the line. Even if the cab is 100% crap you can atleast use the frame and the suspension parts.

Second if you dont want to wait on the parts truck you can change out your springs with 3/4 ton then I would box in the frame from the cab to the rear bumper. However I dont think you need to do the 100% back. Just do it in sections so it strengthens the frame. Then I would also throw some braces between the frame rails so it adds strength between frame rail to frame rail.
After this is all done I would go at it with the truck. Then if your 1/2 ton rear end breaks you find a good used 3/4 ton to swap it out.

Hope that makes sense.

Oh and one last thing, I would also try to find an old 350 (atleast) because you will need as much torque as possible to keep those wheels turning with a loaded bed.

[DreamRyder1963]

Thanks for the reply that sounds like a plan.

[bdeese]

nice to see this thread. I'll be doing the exact opposite soon and it's good to see the differences listed out here. I'm actually now thinking about buying a short bed C10 and swapping my cab and front clip over (my cab is in great shape and it's sentimental, granddad bought truck new).

[Carl Spangler]

Originally Posted by DreamRyder1963

Recently my buddy and I picked up a 1969 c10 longbed for $400. The bed and most of the cab is shot but it runs and does have some nice parts left intact. One of the main reasons we bought it is because he was looking for a truck he could use as a farm truck and not care if it gets dented and beat up. He has bought a flat bed to replace whats left of the 8 foot box and we would like to increase the hauling capacity of the truck. He is wanting to make it effectly a C20. Beyond swapping the leaf springs, what else do we need to do?

If this is just a farm truck I'd seriously consider just using as is.

I'd also keep an eye out for a real C20 and just sell this C10 when you find the C20.

cheers
JohnG

[WorkinLonghorn]

For what it's worth, I used a 1969 C10 (actually it was a GMC 1500, same truck) for heavy work with just upgraded rear springs. I hauled all manner of very heavy loads with it with few problems.
However when I got my current GMC 2500 I noticed a dramatic improvement in braking, handling, and just the all around feeling that I had the right truck for the job. Heavy duty differential, axles, springs,frame, etc.
Now I put a load of sod or gravel back there and it is like "Is that all you've got?".
3/4 or 1ton is the only way to go IMO.-Brian