Preface:
I have 2001 Chevrolet Blazer rear axle and brakes. At this time I have the stock Vega front brakes, combination valve, and all lines. I intend to install the same era front brakes on the Vega eventually.
The stock HBody master cylinder will not work because it is designed for a set-up with disc brakes up front and drums in the rear. There are numerous resources that explain why and I do not want this thread to get dragged down with that debate.
The goal:
To find a master cylinder that is a direct bolt-in swap, has the right pedal feel and travel distance to allow for spirited driving (heel and toe).
Keep in Mind:
If we consider maximum braking the point where all 4 wheels lock up at 40mph, then;
A bigger bore makes the pedal harder to move and it will need to move less distance to achieve maximum braking
A smaller bore will have a softer pedal and have to travel a further distance to achieve maximum braking
All part numbers and stats are from the Cardone Website
Stock HBody Master cylinder:
The bore size of a stock All Vega brake master cylinder is .75" (3/4") power or manual brakes makes no difference.
The bore size of a stock 1975-and-up Monza brake master cylinder is .875" (7/8"). Does not specify power or manual brakes.
Alternative Master Cylinders
1972 C3 Corvette master cylinder has a bore of 1.00" for manual and 1.125" for power brakes. The same is true of equivalent Camaro and Nova M/C's.
2002 Blazer Master cylinder has a bore of 1.00"
First I used a 1972 Chevrolet C3 Corvette power brake Master cylinder (1.125" bore):
The brake pedal feel is rock solid. Not in a good way either.
The pedal moves about 1" with a significant amount of leg effort before locking up all 4 wheels. This makes heel-and-toe downshifting impossible.
It did not come equipped to accept the pedal rod.
The lines were the correct size and it bolted to the firewall with no problems.
I would not recommend.
Second, I used a 1972 Chevrolet C3 Corvette Manual brake Master cylinder (1.00" bore):
The brake pedal feel is firm. Slightly firmer than the Wife's 2015 VW Passat.
The pedal moves a very natural 4" before locking up all 4 wheels. Heel-and-toe downshifting is still impossible because the gas pedal is too low.
It did not come equipped to accept the pedal rod.
I modified a 40mm freeze plug to act as a pedal rod cup.
The lines were the correct size and it bolted to the firewall with no problems.
100% would recommend!