i have a 90 dx hatch with a b16 and rear disc swap from a 99 integra. brakes work fine but dont have stopping power at faster speeds. i have stock front calipers, stock MC and a 40/40 prop valve. ive bled the brakes numerous times. same result spongy pedal. think i need a bigger MC?

 

hmmmm

 

Whenever I had this problem, I bled my brakes once more and made sure that the brake fluid didn't get too low in the MC.
You probably still have air in the lines???

 

its possible i guess...bled them like 6 times. pedal is firm and brakes stop the car but if you mash the brake pedal it wont come to a dead stop, just slow down