Manual drum to power disc

Any opinions on converting to power disc on factory 351 m code 4 spd car but keep the drum parts

What drum parts are you hoping to keep? Isn't the point to get rid of some of them to make room for disc parts?

On the original build sheet which I have they never ordered the power disc brakes

Simplest, and probably the most cost effective approach, is swapping in a 71-73 factory front disc brake setup. It's not a difficult swap at all.

You will need new spindles, bearings, bearing seals, brake hoses, proportioning valve, proportioning valve brake lines, master cylinder and booster, booster mounting spacer, brake pedal, vacuum port on the block (larger, additional port for the booster), as well as calipers, rotors, brake water shields, and all the fiddly bits to bolt it all together. The best part is - everything is available, although good spindles may take some time if you want to stay original.

I'm not sure if these are still available, or they may have changed names, I think SSBC was taken over by some other company, but when I did mine, I chose SSBC 4 piston Kelsey-Hayes style disc brakes as they bolted onto the drum spindles and was a relatively easy swap. The kit came with all the parts needed except new brake lines, which I would highly recommend regardless. No matter what you choose, make sure you have the correct disc/drum master cylinder. I also added a variable adjustment valve for the back brakes, which was part of the kit.

Be sure to use the correct master cylinder. The MC for drum brakes have residual pressure check valves under the brass seat in their outlets. You do not want those valves on any hydraulic line used with a disc brake as it keep low but constant pressure on the pass. That will lead to excessive pad wear, reduces vehicles performances, cause overheating and warped rotors. Also, often the piston bore size for disc brake system MC is different drum drum brakes.

Are you asking if you should archive the old parts you have removed for a future owner who might want to restore the car back to original?

I don't know what 71-72 Mustang value crowd would say. It may be a selling point. I know the Vette and Chevelle SS crowds hang onto all kinds of random stuff "just in case" so when they sell the car they can include the original stuff for the new owner. Who probably won't change it back.

I converted my Sportsroof to factory power front disc and power steering, and 4 speed from 3 speed. Not a Mach or Boss, so the parts went away.

I converted my 1972 Mustang from front drum brakes to front disc brakes. As Mike Griese has already stated it isn't to hard of a job just alot of time swapping out the drum brake parts to the disc part parts. It is well worth the time to swap from drum to disc on the front brakes. I was able to use all Ford Factory parts for my swap and it turned out very well. If you have any questions just let me know.

I agree with HemiKiller 100%. Replacing the rear drums with Disc is significantly more work and in my opinion not worth the bang for the buck+time. Although having front and rear discs looks great in profile pics. On a street car, I find minimal gain in braking with four disc vs front disc and rear drum.

I went with rear discs on my 70 Mach I. I bought a stock set of stainless steel brake lines for a disc/drum car. What a pain it is bending and flaring stainless, without having the right expensive equipment. Also, you will use a non-stock GM distribution block which requires more tube bending and flaring to adapt it the Ford master cylinder and the front and rear brake lines. What PIA! All that for a minimal gain in braking performance over a front disc/rear drum setup. If you go rear disc, I would not use stainless steel lines, if you plan on bending and flaring them yourself with the typical hand tools, they just can't handle Stainless.

Also, I found the factory-style rear swaybar does not fit around the typical GM-style rear disc conversion kits and you will need to modify/replace your parking brake cables.

If you keep the rear drums and get the stock 70-73 front disc spindles, stock rotors and calipers, or upgrade the front discs ie larger rotors, multi-piston calipers, you can still use the stock front and rear hard brake lines, brake booster and master cylinder, disc brake distribution block and hard lines to the master cylinder, and the brake warning switch.

Would I do it again... not likely, and that's my two cents....

11” rear drum brakes were good enough to be used on the 1966 Shelby GT 350R. They should be fine for the street. (FYI 11” brakes will likely require an external rear brake bias adjustment valve).