I just bought a 79 crewcab 2wd I was wondering if I could just put the crew cab body on the extra cab frame I already have a 78 supercab 4wd that I'm planning on using as a donor. So the big question is do I have to stretch the frame or what would be the easiest (best) way to go?
What is the difference in the wheelbase of the two? If you wanted to make it look original then you would need to stretch the frame super cab frame.. But if I was you, I would get some measurements and shorten the bed accordingly.
Your other option would be to swap the 4x4 running gear under the 2wd frame. (Lots of work but probably more practical than stretching the frame.) both will involve a fare share of fab work
I think another site that begins with F and ends in ification has builders sheets or something like that that have all the frame specs. I found them for my 72 CC so maybe the SCAB's might be there also.
both are long beds I really want to keep it a long bed I am getting the truck tomorrow then I can measure up and see what would be the best. I'm thinking about stretching the frame as long as I beef up the section I lengthen. I should be able to cut from the 2wd frame and put it in my 4wd frame without to much issue right?
Personally I'm not a fan of frame stretching - or even frame shortening for that matter, unless it's on a truck that will be full caged from bumper to bumper & the cage will make up for any weakness caused by the frame cut.
There are guys who do it though and most of their trucks haven't broken in half yet. IF you decide you want to cut the frame make sure a qualified welder puts it back together & that the thing is properly fish plated & reinforced.
if your truck is a true 79 longbed 2wd then its alot easier to doa 4wd conversion usig the supercab parts than to do all the frame work. Im looking at making another crew purchase in the next couple weeks and i hope to do a writeup on it.