Master cylinder is part of a hydraulic system. The parts have to compliment each other if you want them to work. If you have stock brakes and want to retain them then use stock parts from Rock Auto dot com.
If you want to use the big brakes off a NASCAR car that Jon Baer sized to stop a car doing 170 mph then follow his suggestions (he is an engineer who specialized in brake design). Bill Wood started Wilwood Engineering, Inc. back in 1977 doing the same thing; slowing down NASCAR race cars.
The factory doesn't use either Baer or Wilwood on their Corvette or Camaro instead using originally Grilling (the guy who invented disc brakes to slow down RAF bombers landing on strips during WWII), then PBR, then Brembo brakes off of European and Italian sports cars.
Your car was never offered with disc brakes as an option (that didn't happen until 1967) but it shares parts off of the 1967-'70 full size B-body that did offer both the Grilling designed Corvette four piston brakes and starting in 1969 and ending with the 1970 a special one year only large diameter caliper single piston full floating disc brake system.
SSBC, CCP, MPB and most everyone else wants to sell you GM brake parts off of a 1973-'78 A-body car packaged with a special steering knuckle to fit your car. They are equipped with modern metric or non-metric style brakes off a car that weighed far less than your full size car. With Brakes bigger is better, not smaller and size is based upon either GVW (think a big semi truck) or speed as the 213 mph Corvette. Either a lot of weight or a lot of speed needs large brakes to shed the heat generated.
Good news is the Corvette used Impala parts for the motor, trans and front suspension up through 1982 so the brakes interchange (the C3 corvette with a BBC topped out at 122 mph, so the brakes were designed to stop 3,800 pounds going that fast.)
Strange makes carbon fiber rotors and ceramic pad disc brakes that can stop a 2,400 pound dragster in 1000 feet from 330 mph, at least once, but they are large and pricey and require 37 inch tall by 18 inch wide drag slicks to work.