C 20 Questions

[danleaman]

I have a 72 C20 survivor and it's about time to do some up grades. It's a camper special with the heavy Duty springs and rides like it. My question is will some of the later Chevy brake and suspension parts fit on the 72? I would like more modern brakes and a taller rear end ratio (It's screaming at 60 MPH) and of course a smother ride while still keeping it a 3/4 ton. None of the after market folks seem to be interested in anything other than how to lower your truck or turn it into a C10.
Thanks in advance for your Knowledge.

P.S. I'm new to this board and love it! Lot's of information and great pics to gather ideas from.

Thanks again.

Dan

72 C20 Camper special / 350 / turbo 350 trans

[LockDoc]

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Hi Dan,

Welcome to the board!

I can't help you a lot but I don't think there is much later stuff that is a direct bolt on. I also don't think there is a lot of aftermarket upgrades for the 3/4 ton... That is why a lot of people convert over to the 1/2 tons. Maybe someone that has experience in what you want to do will chime in.

LockDoc

[sleepertruck72]

Welcome to the board ! you mention more modern brakes, as in disc in the rear , I assume ? I came across a thread long ago that I will try to find that sells adapters for disc brakes on the rear end. I have spent alot of time looking for direct bolt on swaps and have not found any. It does seem possible to get a rear axle from the newer Chevy 2500HD pickups to get both disc brakes, and some 3.73's It will require some fab work however, hopefully someone here can chime in with actual experience

[raycow]

If you want to keep it 8 lug all around, your best bet would be a later 14 bolt rear. These are available down to at least 3.42, but they are not a bolt-in. Assuming you have coil springs, you would need to weld on the brackets for the trailing arms and panhard bar. 1/2 ton springs are a direct swap and will improve the ride noticeably.

Ray

[danleaman]

Thanks for the responses, I failed to mention that it is a leaf spring truck.

[dibbleg]

I have a 67 c20 and have the same issue with the rpms being way too high going fast. is that more of a rear end gear thing or the trans?

[LockDoc]

Originally Posted by dibbleg

I have a 67 c20 and have the same issue with the rpms being way too high going fast. is that more of a rear end gear thing or the trans?

Either/or... They usually have the low 4:10 rear end gears and if you have the granny low 4 speed you won't get much top end. I think it's a little better with an automatic. I put an s-10 five speed behind the six banger in my '67 C-20 and it made all the difference in the world. That thing is a joy to drive now, 65-70 and that six just purrs...

LockDoc

[eastcoastcivil]

I have a 67 C20 with a bored out 350, 4:10 gears and a 3 on the tree. The only thing I have figured to help it from screaming on the highway was taller tires (I am running 31 inch at the moment), swap ot the rear end to a newer style or install a tranny with an overdrive (I bought a 2004R tranny with a shift kit and will be installing that next). Mine is a 2wd with trailing arms so the ride isn't too bad...but I would like to do some upgrades too so I will be watching this thread... Welcome to the board, great bunch of guys here and loads of info.

[dibbleg]

i have a 283 in my c20.. so what options would i have for the tranny besides a th350, 400. i dont know much about them.

[haysonj]

I put a 14 bolt from a 73 one ton in mine and all I had to do was weld new perchs on it cost me $40 for the perches. I got the rear end for $300 and they do make a disc brake kit for it but I have the big brake shoes on it so I didn't want the discs. You also can still buy all the parts for it and a wide range of gears.

[pmpski_1]

Welcome.

Dan, I've got the same setup, but mines a 71. As far as the brakes go, what do you consider 'modern'? If you're talking about discs, why do you want discs?

I can think of a couple reasons - maybe you're towing, or maybe you've found out what a pain it is to do a brake job on your rear end. But if it's just for having disc brakes, is it a noticeable upgrade?

As far as the rpms at 60 MPH you have a few choices:
1. Taller tires, as mentioned. This should help a bit.
2. OD transmission swap
3. New rear gears
4. Swap rear ends (I think a 3.54 D60 was available as well and should be a straight swap, but they're not as easy to find as the 4.10)
5. Gear vendors OD unit

I'm doing #1, and haven't decided on #3 or #5 yet. GV is at least double the cost, but I'll get to keep the 4.10 for when I want or need it and the GV is bulletproof. But it's a lot of money, and the 3.54 probably would be ok for what I have planned for the future.

Depending on your needs and budget any one of these will help.

[eagleuh1]

5.3 and 4l60e. Also need to get rid of the 4.56:1 gears in the D60. Keeping the 31 inch tires. Good luck with yours, I'd go with the overdrive tranny in your case.

[danleaman]

Thanks for all of the great imput, the OD Trans seems to be the way to go for now. So what is better 700R4 or 2004r? I have heard that the 700r4 has problems, but don't know if that is really true.

Thanks again for all the suggestions, it's my dd and has been for the last ten years.

Dan

[sleepertruck72]

I did forget to mention that I did the 700R4 swap, and it solved the high RPM scream on the highway. My D60 is still geared at 4.10 and I kinda like it.

[danleaman]

I don't have to have disc brakes, I was hoping that there was an easy rear end swap, but I guess not. Also wondering if there is a way to get a better ride with out losing the 3/4 ton rating.

Also as long as I'm asking questions is there an easy way to tell what rear end it has in it? there is a rather large number 60 stamped on it.
I'm not much of a trans and suspension guy, so any help would be great.

Thanks again
Dan

[Ackattack]

for a smoother ride use airbags.

If it's a leaf spring truck, take out a few leafs, add some airbags on top of the springs and when you need the capacity add in some air.

If its a coild spring truck, you could swap to 1/2 ton springs then add in helper airbags or completely replace the coil springs with the appropriate capacity air bag.

You don't have to have the expensive air tank, pump, valve set up a lot of guys have. You can just use a couple of schrader valves since you probably won't be adjusting it a lot.

[capev86]

if you want disc brakes.....get a 2000+ gm 14 bolt w/ factory disc. also, that gives you the new gen diff with 11.5 ring gear. also, you will get a wider track width that will help bring it out to match the front (i hate the narrow rear look). i did a 4.10 third member swap in my 72 burb c20 w/ the HO52 and a borg warner OD on the saginaw 3 on the tree is the last step i have planned. but a 14 bolt swap gives you options for more highway friendly gearing (and better mpg) if you have a big block w/ tons of power or a diesel that can not rev very high.

the stock front disc brakes on these trucks is actually pretty good and they really didn't make significant changes until the late model trucks. my 72 burb (coil rear) rides pretty firm (it is a 3/4 ton after all) but i don't really notice it unless i'm on bad roads. it really isn't that much more harsh than a 1/2 ton and i like the firmer handling and increased capacity that comes from the stiffer pieces. i'm thinking all my truck needs is some modern shocks to absorb impacts and react better.....the truck only has 75,000 miles on it and they probably were never replaced by the original owner.

[pmpski_1]

Originally Posted by sleepertruck72

I did forget to mention that I did the 700R4 swap, and it solved the high RPM scream on the highway. My D60 is still geared at 4.10 and I kinda like it.

I thought hard about going this route, many have done it with great success. I'm not as mechanically inclined as I'd like to be so I stuck with the TH350 so I don't have to worry about the conversion, troubleshooting, fixing problems, etc. Plus the TH350 is pretty much bulletproof under normal use.

There are many threads about 700R4 conversions and the difference between the 700R4 and the 200R4. Both seem to be a good choice.

[292farmer]

these guys sell a complete rear disc kit for the dana 60, im saving up to get it. http://www.blackbirdscustomtrucks.com/index7.html#4d60