[36tbird]

It has been a long time since I did the press fit of the bearing adapter but I remember I used a different technique, spindles in the freezer for a day, adapter slightly warm, pipe and BFH used as required.

Be aware that discs kits on the front usually move the wheel out about 1" per side. Could cause some interference on lowered front ends.

Rear discs are a waste of time and the associated emergency brake adjustment is a major PIA.

I get into a lot of arguments with my friends over this, so some should stand by to get pissed off. You want your front brakes to do 75% of the work. Therefore a proportioning valve is necessary no matter if you have discs or drums in the rear. If you look at new cars, the front discs are larger diameter (bigger moment lever) than the rears and that is how the 75% ratio is engineered in. But, aftermarket kits are usually all the same size so a proportioning or ratio valve is needed.

Drum brakes require less pressure than disc brakes because they are "self energizing", the shoes expand and get twisted into the anchor bolts or each other, depending on design, and a mechanical advantage results. Therefore in a disc/drum combo if you put the same pressure into the front or back, the rear brakes will lock up sooner. You need a proportioning valve to reduce the pressure to the rear drums.

Now having typed out the diatribe let me say that I am not an engineer but a guy who did a technical paper on disc brakes back in college when dinosaurs roamed the earth. FWIW.

I'll leave it to someone else to point out why residual pressure valves are different but also a good idea to incorporate into your old Ford brake system.