At my wits end ...

[eastcoastcivil]

Hey, I have a 68 GMC lwb 4x4 and the frame is pretty badly rusted, I have a lead on a 70 Chevy lwb with a decent frame but it is only a 2wd....can the two frames be swapped? I know the fenders and hood are different, but really all I want right now is a good frame.

[BUDDY]

Short answer - yes it can be swapped.

Long answer - with a lot of work.

You have to find out at least if it's a coil-sprung rear-axle or leafs. Either can work, but the leafs will be easier because you just have to swap in you axle then or leave in the one that's already there.

If the new frame has the trailing arm suspension, there are a couple options to consider.

First - you can keep the arms with the coils & have a very solid & predictable rear suspension. You can then upgrade to an air-ride rear suspension very easily that way & if you want to lift it all you have to do is flip the axle mount from the topside of the axle to the bottom. You'll gain about 4" of lift & have an INCREDIBLY supple & flexible suspenion. The drawbacks are that you probably can't lift it more than that without a LOT more fabrication. FYI - NASCAR uses the trailing arm suspension exclusively due to it's simplicity & adjustability along with it's toughness & reliability.

Second - you can remove the trailing arms entirely & put on the leafsprings that you currently have on your truck. Lots of grinding, drilling, cussing, etc.
But you will be able to use any production lift springs or replacement springs that are available. You will also have the inherent issue of axlewrap that comes along with having leafsprings.

The bigger problem is that the front suspension is going to need work in either case. You will have to remove ALL of the suspension components & the main crossmember underneath the engine. Get a LOT of grinding wheels or be very handy with a torch. It will take some work to get it down to just the frame. Then, once you have just the framerails forward of the cab to the radiator mounts, you should be able to easily re-mount the front spring hangers, locate the existing hole for the rear of the fronts springs, (or drill a new one), & slam you're spring underneath there. Again, if you are going to lift it there are several products out there. One place to check out is diy4x. Apparently, Kurt is a great guy to deal with & he already has a lot of the products you'd need to make this conversion happen without chopping apart the truck you already have. You could build the frame & still drive the truck as is, (if you are driving it currently).

IMHO, (which you can take or leave), I'd get the frame, in either case, & build it the way that you want it to be & right the first time. That way you'll have a solid foundation for you're truck once you get to the point of swapping the body over. It'll cost both time & money, but it'll be worth it once you're finished & who knows, maybe you can recycle your current frame to somebody else.

HTH,
Buddy