These cars don't need power brakes IMO. I upgraded my wagon to factory Kelsey Hayes discs a couple years back, and it stops just fine with a manual master.
I got everything from the spindles out from a member on this site. And I used the parts list in the how-to article for everything else.
My Scamp has factory manual discs also, and I never had a problem stopping it either.
Both cars are heavier than yours.
