1991 GMC frame under 1970 truck?

[rockape60]

I have a 1970 Chevy C-10 ½ ton short wheel base stepside truck that I am working on restoring. I also have a chance to buy a wrecked 1991 GMC short bed truck. I am contemplating on trying to mount my 1970 body parts to the 1991 frame and chassis, keeping the 1991 engine, transmission, steering, suspension etc.
Do you have any knowledge as to weather this is feasible? I want to have a later model fuel injected engine, but I could gain many more nice little things if this idea will work. The wrecked truck reportedly has no frame damage. I haven’t bought it yet because I have no use for it otherwise.
I am a machinist and have a good friend who is a welder so we can make some modifications. I just don’t want to get in to a super major project trying to do this.
I would appreciate any info you could give me about this.