moving parts from one sub to another can i do it????

I just got a 1981 3/4 ton sub, and a 1991 1/2 ton sub. The body on the '81 is very rusty, and the body on the '91 is in fairly good shape, but the Motor is trash. First how hard will it be to do the engine swap, and still have the fuel injection, just change the intake???? Second, I would like to put the 3/4 ton axles under the 1/2 ton does it just bolt up, and would one of the drive shafts work. I know i will have a lot more questions down the road, I do have just enought mechanic ability to get me alot of trouble. Thanks for all your help so far.

 

does anybody have any answers to this or do I need to go else where??????

 

The frames are differenced from a 1/2 ton to a 3/4 ton. Not too sure but if they are 4x4 you might be ok. how big is the diff from the 81 to the 91 how many stud in the wheel if they have the same amount studs you might be in luck. Pic's of a few spots diff's frame near where the diff springs go on . check the frame just under the cab between the box cab to see if the frames are same size. If the frames are not same then the only thing you can do make the 1/2 ton in to a heavy 1/2 ton you put more leafs on same as the 3/4 set up heavy duty shocks rear sway bar sway bar in the front a single drive shaft should work if it the right size.
post some pic's of the parts of the sub. Are both diffs 12 bolt, 14bolts or 10 bolts.

 

1/2 and 3/4 ton frames are the same, 1 tons are different. As long as both are 4x4 they will just bolt up, might need a conversion u-joint (Napa #447) for the rear depending on what trans/t-case and shafts you use. '81 should have a 28 spline 10 bolt front/14 bolt ff rear, '91 should have a 30 spline 10 bolt front (differential and shafts are different)/10 bolt rear. The '81 will also have the older style parking brake setup, so you may need backing plates and cables from a '84 and newer 14 bolt (ff or the smaller sf) with the same size brakes.

Not sure about the motor/intake.

 

For the motor you will need to relocate all the sensors, heads, intake and everything else on up from there. Also if your going to have to motor out go ahead and change the oil pump, timing chain and all the seals.