For months I have been trying to get brakes on my 31 Ford Sedan delivery. I have replaced everything with new parts. I have disc brakes on the front with GM calipers a 2lb residual and new lines.I just replaced the master cylinder with a new corvette style and a new combination valve and 7" booster. I have new lines running to GM calipers on the rear with a 2lb residual also. They are the regular style calipers not the small metric ones.I have bled the brakes until I'm bleeding and can't get a pedal. I checked pedal ratio and it's about 6.1. I get some resistance until I open the front caliper. One push of the pedal and everything goes away. Pedal can be pushed to the floor with my finger. I spent hours bleeding the master and lines and nothing. I have asked you guys before on this problem and wound up taking everything apart and using two single master cylinders from Wilwood and got a pedal but wouldn't stop at 60MPH at all at 40 it would stop just barely. So I figured if I buy a whole set up matched and tried it that would do it. Well, nothing I have done has given me brakes. I have never had a problem before when doing brakes. I have built 4 cars and this is driving me nuts. It has to be something simple I'm over looking. Please if anyone has any ideas I need help! The rear disc brakes are a bolt on kit. That I purchased. Thank you!!