70 roadrunner hemi power brakes/non power

looking to remove power brake booster and swap to manual car has factory disc brakes, what master cylinder to use and does porportioning valve need to be changed as well?

If the MC has the shallow circular recess around the bore of the rear piston about halfway down which is needed for the manual brake pushrod snip of neoprene to lock into then I would keep it & the prop valve & see how it acts. You might very well be fine as is & you would not have to even open up the system.

On my 70RR, front disk brakes from 73 A body I have no power booster. My MC is from a Dakota truck works fine..

Just my $0.02...

Wondered why you are removing the Booster. Is the booster a non Hemi Booster and are having trouble with clearance to the Valve cover. If you do it with a complete conversion via someone like Wilwood you likely will not be doing it again until your return to the stock with a restoration to the Runner. Keep all parts you take off in a box for the future.

I did this combo on my 1970 Hemi Challenger. I used a master cylinder with the smallest bore I could get for the best hydraulic ratio. Sorry, I don't have the exact number. I did not change anything else and the brakes work great. I believe they are over-boosted with power brakes.

Its the correct hemi booster and brackets the booster is shot i dont have time to have it rebuilt just want to replace with correct looking and functioning non power front disc brake master cylinder which one do i use?

I believe the manual setup uses a different pedal linkage... basically more leverage (and pedal travel) to get decent braking with manageable effort. Re-pop dual diaphram boosters are available (Dr Diff, MBM) suggest one of those... or new pedal linkage and likely smaller diameter master with manual brakes.