1974 C20 Rear Axle Question

[Super_Dave]

I have closed a deal on a pristine 1974 C20, 350, 2WD, M40 TH400, 14B 3.73 differential. I am collecting information for a future build. http://67-72chevytrucks.com/vboard/s...d.php?t=655783

I will be doing the ECE 2.5" C10 Drop Spindle kit. I also want to swap out the rear axles for a set of Dutchman axles that will be drilled for matching 5x5 C10 bolt pattern. This will retain the HD C20 parts but open up more wheel/tire combinations.

What I need to know, without disassembling things: Are the OEM C20 rear axles the C-Clip type of the Press On Bearing bolt in type?

Thanks!

[andrewmp6]

The 14 bolt came semi float and full float and neither of them uses a c clip.The semi float has the bolt in bearing plate like a 9 inch the full float you pull out the axle from the center of the hub.Easy way to tell which you have is pull off a wheel and look at the center of the rear wheel hub.If the hub sticks way out and covered in bolts its a full float.The semi float will look like a normal axle.

[PGSigns]

Like Andrew said first pull a wheel and see what you have. If it is a full floater than a new rear is needed to get where you want to go. Then you will have to decide on what rear to go to. A 12 bolt would be the easy way to go.
Jimmy

[andrewmp6]

Yeah a 12 bolt from a 73-87 truck will bolt right in and have the lug pattern you want.If it is a full float 14 bolt you can sell it easy.

[Mike C]

If you are swapping the front, swap the back as well makes more sense. You don't need the strength of the 14 bolt it sounds like. Mostly for load carrying and you are negating that with the front.

Easiest way to identify the 14 bolt is the full float has a bolt on pinion retainer. (Look at where the pinion yoke enters the housing, if it has bolts around it, it's full float.)

But the semi-float 14 didn't show up until the early 80's so I'd bet $ you have the FF 14 which would have been original.

[Super_Dave]

Thanks guys.

I have a partial 1979 donor chassis, sandblasted and primed, (front clip) with a 12 bolt. It was going under one of the 1974 Internationals I have, but I think it has a new home!

Dave

[Super_Dave]

Okay... since I have a 1979 1/2 ton Chevy front frame clip and 12 bolt rear end, I will be using the parts from the clip to change over from the FF 14b rear. That part seems pretty straight forward. The spring perches on the 12B were removed, so I will I will be replacing them to work with the C20 springs after removing some leaves and doing a flip.

As for the front components, I am assuming (and correct me if I am wrong) that the 1/2 ton parts are interchangeable with existing mounting holes in the frame.

Also, what other steering parts (TRE's etc), if any, from the C20 cannot be used? I know I need new 1/2 ton ball joints and will be adding 2.5" drop spindles and 1" drop coils.

I am trying to avoid having to swap the entire cradle over, as I will be doing the engine swap in a couple of weeks and need to reduce the downtime of the C20, as I need to keep using it for the time being and won't be ready for the full suspension swap for several more weeks. If it's a bunch of existing parts swapping, I can do that with the new engine in the truck.

All insights and advice are welcome!

Dave

[andrewmp6]

I believe you can bolt in the 1/2 ton a arms and i know the tie rod ends are different sizes between the two.Not sure if you can just swap the tie rod end or do you have to swap the whole steering linkage.

[Super_Dave]

Originally Posted by andrewmp6

I believe you can bolt in the 1/2 ton a arms and i know the tie rod ends are different sizes between the two.Not sure if you can just swap the tie rod end or do you have to swap the whole steering linkage.

Thanks Andrew,

I am preparing myself to replace all the steering components and just use the 1/2 ton UCA's and LCA's. I figure to stockpile all the parts and then get it done at my brothers front end shop.

It will most likely take longer to swap in the 12B rear end than replace all the front components, as I need to get the spring perches welded on, maybe locate a set of 1/2 ton springs in the pick-n-pull, and run brake lines, etc., as well as redo all the brakes.