My 1972 (manual everything) F250 4x4's motor (390) suddenly went Tango Uniform. So I start hunting around and find a 1973 F350 4x2 Chassis Cab 10,000 lb. GVW with a running 390, Factory A/C, Dana 70 rear axle, power steering, and vacuum assist brake unit. I initially just wanted the motor since I'm dealing with major changes between 1972 and 1973. . . . but now I'm thinking about a few things:
1. Could/Should I swap in the Dana 70? It's a factory Dually . . . . might work?
2. Definitely do the well documented (here) brake booster swap into the 72.
3. I can't use the Factory A/C, but I got the '73 running today (smooooooth) and can hear what I think is the air compressor building pressure and then the 'Pssst' like it has reached psi limit . . . . so now I'm thinking about an on board air system using the cast iron behemoth a/c compressor and putting it in my 72 4x4. Has it been done? Can it or should it be done? Hmmm.

4. Since I use my 72 4x4 for hauling firewood why not add in the leaf pack along with the Dana 70 rear off the 73 F350 . . . possible?

5. I wonder what other cool stuff I could steal off this 73 F350 for my 72 to make it better. The front disc brakes are all new on the 73 but it's a 4x2 so it doesn't look good for a bolt up.

Or, do I pull the motor and part out all things not necessary and scrap the rest?
Cheers, Hello, and thanks for your input. My first post after a year of reading all through this forum (but surely not all of it).

 

The a/c compressor can be used to pump air. I knew one guy who did it. 90 psi was max. I'm not sure how he kept oil in it though.
No reason you couldn't use the 70 rear. Driveshaft length will probably be different and you might want to measure the spring pads, they might need moved. Also since the brakes are probably bigger on the 70, you might have to fiddle with the brake proportioning.

 

willowbilly3 thanks for the reply.
While 90 psi isn't a lot, it should function for what I would need out in the boonies (Flat tire, blow the junk out of my chainsaw's air filter, etc.). I have been saving one of the stainless steel water type fire extinguishers for use as an air tank. Read a thread a couple years ago on a 4x4 site about how to plumb one etc. Should fit nicely inside the frame rails. Do you know if the person that used the AC compressor ever wrote about how he did it on a forum etc.?
I was wondering about the oil as well, the manual mentions that in normal operation the oil can circulate in the AC system and then return to the pump . . . sounds like magic.

Definitely looking at the Dana 70 on the rear, although I must confess that I'm in a real jam and just have to get the F250 running so I can go cut some fire wood. If the 70 looks like a fairly easy swap I'll just do it, but I may have to wait until money starts flowing to do much more than a bolt on deal. It's also got 3.73 gears and an open diff which I'd want to change to a true track or some such and put in lower gears . . . more money.

Here's an important distinction/question: Since the Dana 70 is set up for Dual wheels and since I am NOT running duallies on my F250, when I bolt up my standard SRW rims to the Dana 70 It's possible my track width in the rear could change some . . more homework for me. Any favorite suppliers of rims with different backspacing etc.? Now I have to learn that lingo as well.


Brake proportioning. I must admit I know absolutely nothing about that. Are there actual adjusting screws? I'm trying to recall if my truck has the arm connected to the frame to self adjust in some mysterious way the brake pressure at the rear brake line manifold when more weight is in the truck . . . can't recall which old truck I had did that. If you could elaborate a bit that would be good.

 

If you are serious about running an A/C compressor for on board air, here is a write up for using your York compressor.

York Compressor for On-Board Air

 

Thanks Greenhiboy. Perfect. I'll give it a good read.
I had no idea the CFM the pump was capable of. WOW.

 

So, greenhiboy has some good info here and then my love of all things original kicked in and I'm thinking there might be some person out there wanting to put a complete factory AC unit in their truck. Are folks looking for these or is the change over in refrigerant a problem. I can't use the AC and don't really need or want it other than cannibalizing the compressor for an onboard air unit. Any suggestions on where to post the availability of this factory air system? It looks absolutely complete under the hood and interior as well, excepting the louvers on the driver side vent. There are very few parts on this 2wd F30 I'll be using myself and the paint and sheet metal and glass etc. are in good shape. I know what it's like hunting for the right original stuff and this truck's cab is better pretty darn solid. Desert rig and must have been in a shed or something most of its life.

Cheers.

 

The swap is fairly straightforward based on the good info here. I tested the vacuum assist unit before getting ready to put it into my '72. I noticed that where the vacuum hose enters the can the grommet around the plastic elbow entering the can is cracked. Are these parts available still or am I looking at having to buy a new one and turn this one in as a core? Some silicone caulk?
Thanks.