2 wheel drive to 4 wheel drive

[Blackdog3]

Hey gang, i might be taking on yet another project. I found an sweet 87 C20 in MI today. I am going to MI in about 24 hours. I have a K 20 frame and axles. I figured out swapping stuff over but i am thinking how hard is and what do i need to swap it over from the 2 wheel drive to 4 wheel drive. I have the 3/4ton axles springs and what not on the doner frame. Any thoughts?

Chris

 

[HotRodPC]

My opinion is, transfer the body to the K20 frame and powertrain. You'll be way ahead of the game doing that. Its been discussed many times on many forums, the 2wd to 4wd conversion is NOT worth the time effort and funds when you'd have to acquire a K frame and suspension anyway to do it.

 

[Mr Clean]

It a true pain in the ass. I helped a buddy do that years ago, and it was never rite. I don't know what we did wrong, but he ended up buying another wrecked 4X4 and swapping the body to it.

 

[HotRodPC]

It a true pain in the ass. I helped a buddy do that years ago, and it was never rite. I don't know what we did wrong, but he ended up buying another wrecked 4X4 and swapping the body to it.

Yep, its better to transfer a good body the K frame always. However, do remember to keep the center hump out of the K cab cuz you have to retrofit it to the 2wd drive cab. When and if I do mine, I want to make mine a removeable hump by cutting it 2 inches oversize then putting threaded bolt holes about every 6 inches with a rubber gasket to make it air tight.

 

[bucket]

If you have good equipment and are handy with a torch, swapping everything to the current frame can be a better option. It seems that most people that don't like this method, only have basic hand tools, a drill and a grinder.

If you have access to a shop with a lift, have a good compressor with lots of air, a good air hammer, a good low-speed hi-torque drill, a nice torch (and know how to use it), and a nice assortment of jacks... then the frame swap route becomes less appealing.


If I were going 4x4 on a Blazer, Burb, or Crew Cab, I likely wouldn't consider swapping the entire frame. I would consider a frame swap on a reg cab truck, especially if swapping the motor and tranny too.

 

[sean1960]

Each method has it's pros and cons. One method your swapping frames and or bodies and the other your swapping cross members and spring hangers. Your choice just depends on the equipment you have on hand. If your planning to lift the truck for more tire clearance use a 3" body lift and the short center hump of a 2 wheel drive cab won't matter.

 

[Blackdog3]

I didnt go to MI so i bailed out... still gotta find a body for that frame someday!

 

[Joshua8336]

i too was thinking about doin this once, i was gunna just unbolt the k members and swap them over, the put a limited slip in the rear, but you have added the benefit of having another rear end, GOODLUCK! and let us know how it goes

 

[Chevtruck]

Make sure you measure the thickness of both of the frames. I was going to swap the front axle from a k10 to a c10. I know it can be done , but when I measured the k10 frame was thicker. I would check that before you start drilling.

 

[bigben129]

Did you try this? Thinking of doing my own swap

 

[DoubleDingo]

Yep, its better to transfer a good body the K frame always. However, do remember to keep the center hump out of the K cab cuz you have to retrofit it to the 2wd drive cab. When and if I do mine, I want to make mine a removeable hump by cutting it 2 inches oversize then putting threaded bolt holes about every 6 inches with a rubber gasket to make it air tight.

I agree, if you do this, switch the body over. Much easier indeed.

Hot Rod, I thought the center hump in those were removable. I know they are in the older trucks. In the Shop Manual they show installing/removing the transmission from the opening in the floor. The 2WD trucks or those without the HD transmission do not have removable humps, but the 4WD and those with HD transmissions have the removable hump. You need the flange for the front part of the hump and that is not removable, but the hump bolts to the flange and the floor. Is it different in the squares?

Edit: This is the cab of my '65. This truck came with 3 on the tree and has the low hump. I have the flange and the high hump to switch it over to the HD 4 Speed. You can see how the low hump cabs are set up to accept the high hump flange and the hump itself. Just have to cut enough floor out for the hump to sit on and bolt it up.

 

[HotRodPC]

Yep, but the 81 up squares don't have bolt on humps, with exception of the 1 tons with SM465 or 4x4 I do beleive, unless the pic I seen was the older 80 on down. Even the 80 on downs were not all bolt on humps. I also the flange is different from 73-80 truck to 81 up trucks otherwise, I'd just snag a bolt on hump from an 80 on down and them cut and drill holes on mine. Worse case scentario, I'll just have to cut out the hump from the fo buh fo cab. And when I do, I"ll be cutting some extra, and hope to make it a bolt on or screw on hump. And then who knows, I don't like body lifts, but I might just do a 2 inch body lift, maybe it has to be 3, not positive just yet on that, but avoid having to cut the hump by doing a body lift. Also, if I found a 1 ton frame, and used a 1/2-3/4 ton frame crossmember I tihnk I'd be OK too, cuz the 1 ton frame if I recall, is taller, so the that extra distance might allow me to use a 2wd drive cab too. We'll just see when I get that far.

 

[DoubleDingo]

Now I wish I had looked under the carpet in my dad's '79 GMC 4x4 when I had the truck. Sounds like you have a fun project ahead.

 

[BadBowtie87]

hmm

My opinion is, transfer the body to the K20 frame and powertrain. You'll be way ahead of the game doing that. Its been discussed many times on many forums, the 2wd to 4wd conversion is NOT worth the time effort and funds when you'd have to acquire a K frame and suspension anyway to do it.

how hard is it to transfer a 2wd cab to a 4wd frame? do the body mounts line up? i have both and want to do this but cant seem to find much info on what exactly is involved in doing so....

 

[HotRodPC]

We have that info all over on here. Yes, it's a bolt on swap. Just save your 4x4 hump. You'll have to cut it out of the 4x4 cab and either weld or bolt into the 2wd cab. Now if you have a high hump SM465 2wd cab, you might be good to go already.