I have a 78 f250 supercab rwd and am wanting to place on a 4×4 chassis,my problem is that I cannot find an f250 4×4 supercab chassis,but I have found several f150 4×4 supercab chassis.So now my question is besides the fact the f250 has heavier suspension & larger differentials than f150,are there any differences between the the frames themselves?i.e. is one built heavier than the other, thicker gauge steel?

 

I was getting ready to say yes, they have different frames but I looked up the part numbers and the '78 F150 4WD 155" WB Supercab and the '78 F250 155" WB Supercab 4WD take the same frame, P/N D9TZ-5005-V.
It also shows the frame modulus (measure of strength) as 6.67 for one and 6.76 for the other but I think that's a typo.
One other thing you need to consider is most states go by the frame VIN for title purposes, so if you swap frames, you'll need to (or at least should) retitle your truck.

 

Thx for the help,I appreciate it. As i live in Canada we use cab/body VIN# again thank you.

 

78/79 4x4 F150 (SC only) will have front leafs versus the normal coil spring and radius arms set up like all other regular cab 4x4 F150's. And have a 5 lug D44 front axle and a 5 lug 9" rear axle.

All 78/79 F250 reg cab or SC will have leaf front suspension and either a 8 lug D44 HD or a D60 (if you are lucky) and a 8 lug D60 rear axle.