[b-man]

Back when I was converting my 1964 Tempest to manual C6 Corvette Z06 4-wheel disc brakes, Tobin at KORE3 who I purchased the brake kit from recommend using either a 15/16” bore GM or a Wilwood 7/8” master.

I ended up going with the 15/16” GM master (1977 Malibu), mostly to save money and to be able to readily source locally a replacement master if needed. I did install a Wilwood adjustable proportioning valve in the rear brake circuit. Stalled project so I can’t tell you how it worked but I’m confident it’ll be right.

On my 1964 Le Mans convertible I’m using a 1” bore GM master (1970 Firebird) with factory 1969 GP 11” front discs and 9-1/2” rear drums. I was replacing a leaky 1-1/8” master and the softer pedal with slightly increased travel made stopping much easier to modulate with reduced effort. Manual brakes as well.