Manual disc brakes vs power disc brakes questions

[ottd9990, post: 1971366728, member: 47458"]Ok, thanks Matt! I will try to find the parts.[/QUOTE]
Is your brake system stock. If so look at the chart 72bluNblu posted in post #11.

It shows V-L car line with 2.6" calipers and manual disc brakes as using a master cylinder with a 1.03" bore. That equates to 1&1/32" bore in fractional size. According to rock auto a 70s plymouth volare/aspen used a master cylinder in this size in aluminum. It is a 2 bolt master cylinder, and requires a 4 bolt to 2 bolt adaptor. The cheapest i have found these aside from making one myself was dr diff at $38

It shows a power brake master cylinder for V-L car lines as .936 bore. So A bodies used a smaller bore master on power brake cars, and a larger bore on manual brake cars.

I can only assume with power assist a larger bore master was unnecessary and made the brakes touchy. With manual brakes a bigger bore was necessary for the brakes to work properly without power assist.