Brake troubles

Your MC is for drum-drum cars, but "should work". Does the pedal feel like it is bottoming out? Unbolt the MC, but not the tubing and pull it out enough to see the rod from the booster. There is usually an adjustable tip. Adjust so it just barely touches the MC piston as you bolt-up. Might have too much gap. If any air in the system, the pedal will be too springy. Need to flush thru new fluid every few years in VA anyway, which will also bleed out air bubbles. If you use DOT 5 silicone, no need to flush.

I prefer the newer 2-bolt alum MC's. You can buy a 2-4 bolt adapter plate ~$30 ebay.