F-BODY Brake upgrade with all new rotors and pads

[sho89mtx]

SO had a guy install the f-body brake upgrade and all new rotors and pads on the rear from ZZP and when I got it back, the brake pedal was way too spongy and it's now back with him trying to get fixed and he can't figure it out. The f-body upgrade is suppose to be a huge difference in braking power, and after he installed everything, the brakes were actually much worse, i had to pump them just to stop. That's the last time I use this guy! I had a guy before, but this guy said he could do it much cheaper, apparently he can't!

[Psych0matt]

My guess is it isn’t bled all the way. 

[Walterintx]

Did he put a different master cylinder on the car?  I read before on another forum where you had to put a bigger master cylinder on with certain larger calipers to make up for the increase in fluid needed to push the larger diameter pistons or else end up with a very spongy pedal.