3/4 ton crew cab long bed to 1/2 ton crew cab short help

[dragn91]

Picking up a new beater truck it's a 1980 crew cab long bed 2wd c20. I want to swap out the 3/4 ton suspension for 1/2 ton mainly to improve gas mileage because I'm sure the current rear has a low ratio and I need all the mileage I can get out of that 454 400 turbo combination. I also have an f450 diesel so all my heavy pulling will be done with that this will haul the occasional load of scrap , hot rod parts etc.. mainly need to get out of this minivan but still have room for my growing family. I'm no stranger to welding and fab. But this trucks getting done on a budget over the next couple years mainly trading for parts not buying. I'm looking for info on the half ton conversion my main questions are will half ton spindles go right onto 3/4 ton ball joints without a problem? Or will I need to swap the control arms also. I'll probably just cut off a coil or two to get it sitting better and flip the rear or make up some lowered shackles and hangers both I have done in the past but never on a square body. As far as the rear goes will a half ton rear slide right in and bolt up or will I have to move the perch mounts and shorter or lengthen the drive shaft? If I need to shorten the drive shaft I'm going to wait unit the short bed conversion to change the rear out. Also wondering if there's a way to use a 6 lug rear and front somehow I have a set of crusty Boyd cottington 20s I got for free I'd like to use if I can after stripping them and powder coating or painting. Last questions are how much and where do I cut for the short bed conversion the beds the worst spot on the truck rust wise is why I'd like to convert it but if I find a decent long bed I may still keep it haven't 100 percent decided on it yet. Sorry for all the question I just need to get my ducks in a row with two kids and 3 jobs not much free time lol

[Hankster]

6 lug swap ain't nothing! just get LD (light duty) 3/4 ton stuff. With it being a 3/4ton i would guess you have the 1.25 inch wide rotors, just get the newer six lug ones that go right on, then find a 6 lug rear.

[dragn91]

So no spindle change or anything? What year 3/4 ton rotors should I order then that would be awesome if it's as simple as swapping rotors. This trucks a 1980 squarebody

[Hankster]

check out this thread, http://67-72chevytrucks.com/vboard/s...d.php?t=629578

[dragn91]

Thanks but I'm still confused it looks like I still need to swap spindles to the newer body style 3/4 ton light duty or do the newer rotors take the same bearings that my truck will have? If I have to swap spindles I still will but will I need a different tie rod end? It looks like the ball joints will be the same. What years will work besides 99?

[Mr.green]

Seems like a lot of work for a miniscule gain if any.

[dragn91]

I can probably get all the spindal/brake parts for 50 bucks from the local u pull it and my neighbor wants to buy the rear under the truck for 300 plus his 6 lug rear so for probably 75 bucks I can run the rims I all ready have and hopefully get better mileage because his rear has 3.73 and mine probably has 4.11 or 4.56 or something like that being a 3/4 ton camper special bbc truck

[Hankster]

Yeah, it outta help MPG,

http://www.earlyclassic.com/catalog....onversion+Kits Theres a way you can get just the disc..

[Hankster]

http://www.earlyclassic.com/catalog....onversion+Kits

heres just disc 6 lug

[Mr.green]

I think I would start with figuring out what gears you have. my crew cab c30 camper special, dually big block came with the standard gear ratio, 3.73. Anything else was a special order.

You might get 1 mpg more if you drop from 4.11 to 3.73.

Seems to be a lot of work for maybe getting 1mpg.

[streetstar]

Originally Posted by Mr.green

Seems to be a lot of work for maybe getting 1mpg.

If that ---- but perhaps going from 9 to 10 mpg's will be a roaring success

[Jonboy]

Originally Posted by streetstar

If that ---- but perhaps going from 9 to 10 mpg's will be a roaring success

A 10% increase isn't bad in anyone's book!

[tinydb84]

To go from C20 to C10 you will need:

Front
New LCA (or the POL conversion spindles)
New brakes
New wheels

Rear
Move your spring pack in (I believe)
New rear end
New brakes

You need to shorten the frame 14'' in the front and 6'' in the rear.

[Jonboy]

Originally Posted by tinydb84

To go from C20 to C10 you will need:

Front
New LCA (or the POL conversion spindles)
New brakes
New wheels

Rear
Move your spring pack in (I believe)
New rear end
New brakes

You need to shorten the frame 14'' in the front and 6'' in the rear.

The 1/2 ton suspension is different from the lower control arms out; I was able to keep the front calipers when I swapped. In the rear, you can reuse your springs, but the hangers will have to be changed to 1/2 ton units (the 3/4 ton hangers mount the springs too far inward). The upper shock mounts will have to be fabricated also, the 3/4 ton has them inboard of the frame, where the 1/2 ton rear mounts the shocks outside of the frame.

[50seven]

From your post it sounds like you would like to remove a lot of weight from the vehicle, shorten the frame, change the diff, bolt pattern, etc. The 3/4 frame probably weighs a fair amount on it's own.....

Might as well just swap out the frame with a 1/2 ton burb/truck combo. Might still have to slice and dice one to get the right length that you are after?

Drive the truck until you get another frame ready and then do an old switcharoo. Just a thought?

[KQQL IT]

We reamed a 1/2 t ball joint to accept a 3/4 ball joint. And 1/2 t front brake hoses.
And put a 10 bolt rear end with a 3:08 gear. And left the spring hangers and shock brackets alone. Fabbed new spring pad and 3/4t shock brackets on the housing. As far as the frame you're on your own.

[dragn91]

Hey KQQL IT did you ream the spindal? Or the lca for the 1/2 ton ball joint I know the upper just bolts in and I'd probably do the same as you and just weld new leaf spring mounts on the 1/2 ton rear. Hopefully I'll have this big rusty pile at my house tomorrow so I can fix the brake line which is the reason they stopped driving it and start messing with it a bit. How much can I cut a 3/4 ton truck coil most I did on half tons was 1 and a half maybe it's the same with a 3/4? And if I just flip the rear for now will it sit level or to low in the rear. This is more of a budget beater style truck until my other truck is done then I'll sink some time and love into it.

[KQQL IT]

Pm sent.

[dragn91]

Here's some pics got her for 550 and drove her home has 95k which is more than the guy thought but still a deal. 454 400 camper special I hope I can find a seat for the front or an original style cover I pulled the buckets the p.o. put in and installed a black bench I had. It's got an edelbrock carb and intake and headers with some chappy exhaust but runs great has rust but I'm use to it where I live I'll be putting a bed and fenders on it and fixing the rest. Has no brakes at all but cant find a leak but front bowl was empty. I put a caliper on it because one was stuck and new pads but I ran out of time to work on it tonight can't wait to get it a little more fixed up

[dragn91]

[dragn91]

here's the worst spot has a couple holes in rockers but floors and cab mounts are solid

[dragn91]

Got some time to mess with it this morning before work my Sunday job and finally started to get a pedal and found the leak all the way at the rear line just before going into the wheel cylinder. Going to redo the lines up to the front because there kinda crusty hopefully tomorrow after I go get tags

[dragn91]

Anyone know how to check the gear ratio of these trucks without popping off the cover. I tested the rear out this morning on the way to work and it's posi and drives like it has 3.73 or around that

[KQQL IT]

Spid in the glove box

[dragn91]

Couldn't find nothing in the glove box but it looks like someone has tampered with the inside of the box over the years. I got tags today drove it to work and back but brakes are a little sketchy still. Ill get them done this weekend and repack the front bearings. I'm going to get it mechanically sound and then start on the body. I welded up two thrush welded mufflers I love those things I'll eventually redo it all the way back but for now I welded up the poorly welded pipe and added about 3 feet more on each side the mufflers are just under the bed now still need turnarounds but it's going to stay like that a while it sounds so much better and I haven't even installed new collector gaskets yet because I had the wrong size. Just wanted to get the exhaust fumes out the back away from my kids. Anybody have a decent long bed bed near me they would like to part with its the biggest eyesore of the truck