Does Master cylinder bore size really make a difference.

Let's not forget shoes these days suck and can easily glaze the drums and the result is crappy brakes that give out heart failure.

My wagon with all new power drum brakes wouldn't stop for dookie.

Found an old timer with good 'ol parts store shoes, the toxic kind, thing will throw you and all 8 other passengers through the windshield.
Well, 2 would go through the rear window once stopped.