This is an unusual problem on my near complete 1935 Dodge truck. First let me say what I have installed for brakes: a new swing pedal with a 5:1 ratio and a 7" single booster with a corvette 1" bore master cylinder with 3/8" x 24, 2 port outlets. And for the front wheels are original 1935 Dodge truck brakes with new wheel cylinders and new brake shoes. For the rear end is a 70 Nova with self adjusting brakes with new wheel cylinders. All the lines are new 3/16" along with all new brake hoses. This is my problem: if I press on the brake pedal with the engine off (no Vac) the pedal starts to have back pressure fairly soon and does not go all the way down. With the engine running and Vacuum on the booster the pedal goes down fast with no back pressure until it seems to go to the end of the master cylinder, not to the floor. If I drive it with vacuum hose disconnected from booster and plugged, the truck will stop but with a lot of pedal pressure (manual brakes). With the booster hooked back up and driving the truck, when I press on the brake pedal it goes to the same stop as before and not stopping good. I clamped off all the brake rubber lines and the pressing the pedal stop near the top (correct). Then I took one clamp at a time, the rear worked correct, reinstalled clamp. I took off one at a time the two front clamps and they both had the pedal go to same stop as before, (incorrect). Am I missing something because I have pressure reverse bled all the lines, no air. If I can't get to work, I guess I'm going to have to find some disk brake conversion kit $$$.