http://www.classicperform.com/TechBo...tm#testbooster
This link helped alot. Look at booster push rod lenght. After i replaced my master cyclinder i had to adjust about 3/8'' outa the push rod for the new one to work right. Easy wasy is to put the push rod in the booster with no MC, mark the rod with a marker where the bottom of the MC would be when in stalled, then put it in the MC and see if it lines up. Better to be too short then too long there. Too long won't let the rear piston come up to a full pump.