Body and engine swap onto new frame

[willows79]

I have a 79 F250 with a 351M and a 4 speed, 2wd. I also have a 4wd frame and axles sitting out behind my house and I am planning on putting my body and engine on that frame and finding a tranny and t case and I was wondering if anyone had any tips on the easiest way to do the swap and how many parts are interchangeable between the 2wd and 4x4. If anybody has done this swap and has any tips it would be greatly appreciated. I will post pics of the progress when I begin.

Thanks,
Austin W.

 

[Fellro]

It depends what all you want to swap. 77.5-79 all had common frame widths, so the box is a bolt on. The cab mount locations I believe to be common on all 73-79.

For powertrain, it depends on if the frame is 250 or 150. If it has the 8 lugs, it would likely be a 250 chassis. Then it is a question of build date. If it is a 5 bolt chassis, it would be a 150, and the powertrain all used married transfer cases. So if it happened to be the 73-77 250 chassis, the motor and trans are useable with the divorced transfer case. Other than engine, transmission, and rear end, there really isn't much you can put on a bare 4x4 chassis from a bare 2wd chassis.

 

[holtz]

I believe and it is only common to the 3/4 ton 4wd from 73-77 1/2 the back cab body mounts are narrower than the 2wd frames and 1/2 ton 4wd frames and as fellro said the bed bolt widths are different as well and depending on what it had for an engine the perches will have to be possibly changed.

 

[willows79]

Both frames are 3/4 ton frames and they are both 79's. The 4wd frame is complete with axles, a c6 trans and a 205 tcase, and it had a 400 in it that has since been pulled. So really all I'm putting on the frame is body and engine, and swapping transmission out for a 4 speed. So the question I have I guess is that since they are both 79's and they are both 250s, should the body mount bolts all line up? And what are your recommendations on the trans swap??

 

[Fellro]

The body will be a direct swap then. The 4 speed will not bolt to the transfer case, you will need to find a 4wd transmission or stay auto. It would be a good time to go to a ZF if you would like to go 5 speed, but be aware the ZF is hydralic, but the good thing is that the 460 zf is external slave, so the clutch fork is available. The reason I mention the 460 zf 5 speed is that no 400 was bolted to a 5 speed, but the bell is common between the 400 and the 460. You would need the proper flywheel, which might well be the one you have, then use the disc from the 460 if you should choose to go that route.

 

[willows79]

So a ZF from a 460 will bolt up to a 351M/400? What flywheel would I need to make that work?