Hot Rods 1954 belair brake issues

Ok so I’m having issues with my brakes, when I push on the pedal before starting the car the pedal feels nice and stiff than after I start it and drive maybe a minute it becomes progressively softer until it goes to the floor and does nothing, I’ve done a v8 swap and did dual exhaust, the exhaust runs close to the master cylinder, maybe an inch away, I did wrap the exhaust, so obviously the first thing I assumed was brake fluid boiling, so I got heat shield tape wrap and wrapped the master cylinder and and brake lines within a few inches of the brake lines, bleed the lines, pedal felt great, got maybe 2 houses away before the pedal went to the floor and did nothing, master cylinders rebuilt, all wheel cylinders rebuilt, no leaks anywhere and fluid is completely topped off, what am I missing , thank you


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Do you have a picture? , I'm trying to figure how your exhaust is that close to the master ?.

 

Under floor master ? Fire wall mounted?
What kind of booster?
Check valve, 4 wheel drum , 4 wheel disc, boat anchor out the window?

Info and pics some idea of parts used would make it nice so we can help.

Right now all of can comment to make things easier for you is site down and drink heavily !

 

Master under floor, no booster, 4 wheel drum, yes I have a boat anchor... comes in handy, everything brake wise completely stock 54 Chevy, no leaks from wheel cylinders


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I can post pics tomorrow


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