Completely new brake system, no pedal

[CantPutTheSmokeBack]

I have a 1969 C30. I've been working on it for a couple months and my goal has been making it mechanically brand new. I've replaced the entirety of the top end of the engine, steering, suspension, and brakes. Brakes is where I'm having trouble.

I absolutely cannot get a good pedal. It does stop, but it feels like I've only got about 1/2 to 3/4 of the brakes I should, or at least of the brakes I'm used to on everything else I have driven. Not enough to be comfortable driving it. The pedal is soft and I don't feel like there is a lot of travel in it, but I haven't measured it for reference. It doesn't hit the floor, stops solid a couple inches short and again haven't measured anything but I certainly can. I don't believe it's air because I don't get any pedal back if I pump them.

I have replaced everything from the booster out. The booster is for a 1969. I have converted the front to disc brakes so the master (1.315 bore), front calipers, pads, and rotors are all for a 1985 C30 truck. I also had a smaller bore master on it just to see what happened (1.125) and it didn't act any different.

A previous owner replaced the factory rear end with a DRW 14 bolt corporate rear end. I replaced the drums, shoes, wheel cylinders and all hardware. Again, all ordered for a 1985 C30.

I ran all new lines for the truck. 3/16 front and 1/4 rear. I have a CPP PV-2 proportioning valve, and I did get the little plastic bleeder tool to hold the valve center when bleeding.

I gravity bled the whole thing and had assistance bleeding the whole truck 4 times over. I bought one of those air powered vacuum bleeders and had it on the whole truck several times as well. I took the master back off and attempted to bench bleed it again and got no bubbles, then did the lines again. I've probably got 6-8 hours into bleeding this thing.

Maybe I should post in the 73+ section since the brake system is for all intents and purposes a 1985.