'70 GMC cab swap to C30 square body frame

[MS66]

Admins, if this is the wrong place for this thread, let me know. I have an idea to swap a '70 cab to a 1981 C30 frame that already has a Holmes tow body on it. Have not been under the C30 to do any measuring yet, it's still on the trailer. Asking if there is anyone in here that has done this, trying to get a feel for what I'll be up against.
Just found this square body tow truck for my son, his first square. The cab is pretty rough around the edges, don't want to spend hard work on that pile of kit, would feel much better doing it to a '70 model instead. I'm working on a buddy's nephew with a '70 GMC 1/2 ton long bed to sell it to me. First thoughts were a '65-'66 cab, but I'll do the '70 if we can get it. What am I getting myself into?

[kwmech]

A lot of fabrication work moving body mounts around. Firewall to core support is longer on a square body truck

[Palf70Step]

If you do a body lift, it makes it easier to clear the fuel tank area, but as mentioned a lot of fabrication for ANY pre-squarebody cab to be used

[MS66]

Originally Posted by kwmech

A lot of fabrication work moving body mounts around. Firewall to core support is longer on a square body truck

Originally Posted by Palf70Step

If you do a body lift, it makes it easier to clear the fuel tank area, but as mentioned a lot of fabrication for ANY pre-squarebody cab to be used

Ok, thanks for the heads up guys. Working on getting it moving about under it's own accord for now. Probably step back and punt that idea and leave it square until we find a suitable early 1 ton truck to play with.