no brakes on newly installed 440 in 73 charger.

[mobud38]

on my 73 charger i recently installed a 71 440,edelbrock proformer intake,and 750 proformer carb,when car is in park i have brakes,when i put in reverse or drive i lose my brakes and i have to pump in order to get any pedel,i have bleed the front and still no diffence,fuild is ok, master seems ok,car had a 400 motor when i got it and it had  good brakes,thought about putting a vacuum reserve system on but heard they are junk.seems like i have vacuum on idle in park,idle does not change when going into drive.any ideas could help.tks

[idahogrumpy]

Hi, are your rear brakes adjusted with a little drag in them? They should have a little drag when spun by hand, of course when the rear tires are off the ground.   When the engine was put in did you crush the brake line across the back of the firewall or on the inner fender well?
Grumpy 

[68 RT]

If it was vaccum related the pedal would be very hard. Usally when you have to pump the brakes that is a bad master cyl. or air in the lines.

[mobud38]

after searching 7 different auto parts stores for master cylinder found one in stock auto zone,replaced fri,  lots of brakes now tks.