Need help with drive line

[crazyjim]

I took a 1970 gmc 2 wheel drive and short boxed it.My donor truck was a 1976 c 10 front and rearend.I used the 3/4 ton drive line,so what universal will fit it? 3/4 ton one end 1/2 the other end any help thanks.

[mechanicalman]

It depends on your driveshaft.

I assume you have a small u-joint driveshaft and a large u-joint rear-end?

If so, you need an "adaptor" u-joint for the pinion end, a 1310 to 1350 style.

http://www.ringpinion.com/technicalh...plications.inc

You COULD get a driveshaft yoke for big u-joints and use big u-joints on both ends. Probably a good idea if you end up using a custom driveshaft.

http://www.dennysdriveshaft.com/c75_general_motors.html

[crazyjim]

I used the old end on drive shaft so the drive shaft needs a big one and the rearend needs a small one

[mechanicalman]

Originally Posted by crazyjim

I used the old end on drive shaft so the drive shaft needs a big one and the rearend needs a small one

You need a 1310 to 1350 adapter u-joint, easily obtained just follow this link. Install it in the direction that gives you the most grease zerc clearance, otherwise you may have to obtain a grease needle to maintain it.

https://www.google.com/#q=1310+to+1350+u+joint&tbm=shop

[crazyjim]

Ok thanks for your help.

[crazyjim]

I got the u joint, going to put it in Saturday.

[dmack91]

Jim,

We are doing shortboxing my son's 68 C20 too. Just curious, when you did the 76 running gear, how much was involved? Did you use the stock trailing arms or did you go with the 76's leaves? I hear there are some issues getting the front brake lines converted from the 67-72 to the 76 style? What would you consider the most difficult part of the conversion?

Thanks

[crazyjim]

I went with leaves, flip the rearend.Changed all the front end parts off 1976 chevy donor, left the 1970 cross member every thing went right on no problem.Took all the brake lines off and replaced it with the 1976 brake lines real easy.

[dmack91]

Thanks Jim. Did you cut your bed down or find a SWB?

[crazyjim]

yes i did, pain in the ass metal very thin real easy to burn through

[mechanicalman]

Originally Posted by crazyjim

I went with leaves, flip the rearend.Changed all the front end parts off 1976 chevy donor, left the 1970 cross member every thing went right on no problem.Took all the brake lines off and replaced it with the 1976 brake lines real easy.

Hey Jim-
Were the holes in the frame already for the leaf spring brackets or did you have to make them?
MM

[crazyjim]

They were already there.

[crazyjim]

They were already there.