'79 C20 Heavy-Duty Truck

[JLeather]

Long time lurker while I slowly pick away at my '46 pickup project, lately I've been browsing craigslist looking for an older truck to do some cleaning up at my Dad's place. He's accumulated too much scrap, a couple old cars, etc and I needed something capable of a fairly good payload and a fairly large trailer. Also I've got a John Deere D tractor (pushing 5,500 pounds) that I wanted to be able to trailer around. Ran across an ad for a '79 C20, which is now at my place (sorry for the crappy pic, it was dark when I got home).



It was cheap enough and the body is pretty good. Small spot of rust on the front driver's fender and the passenger bed lip is getting bad but for MD that's practically "cherry" . What really surprised me about this truck was the 7,500 pound GVWR. I'm thinking maybe this was a camper truck? The more interesting RPO codes are:

G51 - Extra Capacity Rear Spring
LS9 - 350/4V
YUD - 9.50/16.5 Front Tires
XUD - 950/16.5 Rear Tires
F59 - Front Stabilizer Bar
MX1 - Auto Trans (I think it's a TH400 but the code isn't clear)
J55 - H.D. Power Brakes
N41 - Power Steering

Obviously built for some hauling/towing. I think it's a GM 14-bolt axle, but there's no code for that or what the ratio would be. Out of curiosity, am I gonna be up the creek when it comes to finding some of these parts like the big brake shoes?

So, what does the truck need? Well for starters it wanders around the road too much. Probably needs all the usual front end stuff, and definitely needs a set of tires. To that end, it's running the stock 950x16.5" 8-lug rims. With the big brakes, am I gonna be able to run 16" rims? I'd prefer to swap rims to a more standard size for a better tire selection, although it seems that you can still get Firestone Transforce in 950x16.5" that are a decent deal. Would I need to run 17's to clear the brakes, or do I need to stick to older rims?

That's all for the moment. There's a lot of snow here right now, so I can't really tear into it. Just trying to round up some parts like tires (or wheels and tires), windshield wiper motor, etc.

[Ziegelsteinfaust]

I have a 74 C20 with the HD or Camper package. I run 16" PYO rims from Chevy with 265/70/16 tires.

17's would be a better bet for the long haul, but 16's are good for quite awhile. Because thats is what oems are heading too.

[mrolds88]

Trucks were available with either 16's or 16.5's. No problem with running the 16's. Brake stuff is easy enough to get hold of. Just its more expensive than the 1/2 ton stuff.

[willett]

16.5 tires are kind of a pain to get.

[Remon.]

Nice.

I have a '79 C20 Camper Secial and those are 8200 or 8400 GVWR. Do not know exacly out of my head, but one of the two.

Built like a rock those HD's

[Rubble]

Like others said,16" rims will fit no problem on that truck,I swapped from 16.5 to 16" on an 81 camper special few years ago just because of a bit more selection.Brake parts are easy to come by,just did my 86 couple weeks ago,same 14 bolt full floater & they had all the parts in stock at the local napa.Pretty good for an almost 30 year old truck.Replaced everything except drums.

[JLeather]

Did chevy change the standard bolt pattern for 8-lug wheels in 2010? I've seen a lot of references on this forum that stock chevy wheels up to 2010 will work, but there's a great deal nearby on a set of 2013 take-off 17" rims from a 2500 HD pickup. Will these not work on my '79? I know about the dual-thread lugnuts to be able to run the stock center caps.

[crashz]

In 2011 they changed the bolt pattern to metric withthe upgrades to the new chassis in the HD trucks. So I beleive 2010 and earlier are all the same.