Some good still pictures of the backside of the knuckles and the brakes would probably help lots with the ID. From what I can see, they look to be standard fare late 70's 44HD/D60 stuff, but, I have seen calipers on bigger rigs that look very much the same. What size wheel are you running on there?

As for that terminal block and fuseable link setup on the drivers side firewall, that's actually factory, part of the trailer tow package, there should be a relay tied to that for the trailer charge circuit Your truck obviously has come extra stuff added on there. On my truck, during the body swap, I managed to misplace the relay and it's associated wiring, so, I ended up using that terminal block as a power source for the relays I installed for my fuel pump and backup light(stockers are non-op.) Quite probably something similar may have happened on your truck, and things aren't serving their stock purpose anymore.
I'm kind of surprised I don't have any pics of what is supposed to be going on there from when I stripped out the old cab, I took pretty good photos of most everything.
A good picture of the offending area could help greatly in figuring out just what you have going on there.

 

i have no back up light and the only after market part on my truck are the lift and tires and cd player

 

I'm not really sure what the wiring hear the brake booster is, but I would guess its related to trailer wiring that might have been removed later on. did the truck ever have a winch installed on it? Something I did notice is that the OEM water separator is gone, where those wires come out is about where the water separator is supposed to be.


As for the D44 front end. I agree that this was an option on 1978 ford F250s, so the truss may be the only real mod that was done to it. They were a fairly strong axle with the 8 bolt hubs and bigger brakes already installed. Based on what I learned, they are actually one of the few choices I have to convert to 4wd some day since they can supposedly accept 3.08 gears.

 

i will give u mine i dont know if it ever had winch

 

The good news is that a D60 high pinion should bolt on there no questions asked if you decided to go that route.

 

i will when i get the money

 

Can't really tell from the picture, but it looks like that is being used to send power into the cab.

Most likely was originally for the trailer wiring, but it don't look like that is what it is doing now.

 

maybe it the reasoin i have no brake lighs the fuse it burnt out

 

Brake light fuse is in the fuse block inside.

My guess is when the previous owner pulled the brake controller he pulled a wire off of the brake light switch.

 

so find where it gos and i get my breaklights back