Brake problems

I'm having brake problems with my 1960 GMC 3500 2 ton truck. I just got it from a neighbor and he had just put a new master cylinder on it. It's the duel type, one side for clutch the other from brakes. I put a new booster on it under the cab and bleed the brakes per the place I got the booster, starting with the master cylinder on the booster and them each wheel individually but it still almost takes both feet to push the brake pedal. Also, it takes 3 pumps before the pressure builds up and the pedal doesn't go all the way to the floor. I might also add that I disconnected the vacuum line at the booster with the engine running and it seems to have plenty of vacuum. I also connected a hand held vacuum pump that I have to the inlet on the booster and pumped it up. I put my finger on the inlet after pumping it up and it held vacuum until I released it which I'm guessing means the booster isn't leaking off.