to me it almost sounds like it may be easier to just do a body swap. if you just swap the rear end and leaf springs then you would have 8 bolt rims on the back and 5 bolt rims on the front which would mean you would have to carry 2 spares unless the 250 rotors would bolt onto the the 150. there is other problem you may run into. i know there is 2 different sized u-joint used.

 

How would I tell if the 250 rotors would swap over?
And if I swap the 250 axle and driveshaft the u-joint size shouldn't matter right? Since I already have the axle.

 

i guess it would not matter as long as you are using the same transmission. i have no clue if the rotors would swap over. you may have to change the knuckles to make them fit. i was told my 81 had the same size inner bearing as a 250 but i think in 85 they may have changed things. my dad told me they went metric or something like that.

 

Ok. The 150 has the overdrive-4 transmission, my 250 has the np435 (4 speed with granny gear). Could I use the overdrive-4, or would I have to keep the 435? Maybe switch to a nv(or was it np?)4500?
With the rotors pretty much just research when they changed to metric and see if the knuckles will fit?

 

Sure is a lot simpler and easier to troubleshoot a heater problem than change out a whole suspension. There's not a lot of parts to check. That diverter valve for the heater that Seal talked about is easy to replace and is frequently a problem. It simply allows hot water to pass through the heater box. They either get corroded on the inside or crack and seep anti-freeze. Replacement is cheap. Also, the cable connected to it may not be attached or kinked not allowing it to open. Blower motors can be checked pretty easy too with some direct wiring. One last thing to check is the vacuum lines to the trap doors in the heater box. Service manual is a big help here and worth every penny.Grab the other truck for parts if you need to. If your motor/ tranny needs repair, yank it and put in the slant 6 drivetrain until the V8 is ready to put back in. If you need body parts there they are. Better yet, body patch panels are cheaper than a donor truck. If time is a concern, do like I did and pull the motor and get a long block. You get a warranty to boot.

 

The thing with the body on my 250 is that pretty much every body part except the hood is shot. So I'd rather swap the suspension and what not rather than deal with a whole body swap (moving the cab would be a pain, and then there's all the cutting of the frame on the long box to make the short box fit).

 

Also the frame on the drivers side of my 250 may be bent, my back tire on that side is wearing off funny, I talked to a mechanic and he said either the tires bad or the frame is bent some. My aunt had and accident with it and bent box on that side so it wouldn't suprise me.

 

in my mind that make no sense. how would a bent rear frame cause 1 tire on a straight axle to go bad unless the axle is bent at which point there would be no point in swapping it over.

 

That's a good point, I'm gonna have to find out if the axle is bent or not. As you said, if the axle is bent then there's no point in swapping them.

 

The valve is in the heater hose between the water pump and the inlet of the heater box. These are old trucks and yours may no longer have one. Another common problem if your water pump is old is a partially plugged outlet at the pump.