[RichardJ]

>>with the truck off I have a hard pedal<<
That pretty much rules out bleeding, shoe adj or Metering valve or Proportion valve, unless you had to pump the pedal to get that hard pedal.
>> but when I start the truck brakes go to the floor.<<
As it should, to a point.

A correct size and operating booster should allow three strokes of the pedal should the engine die and loss of manifold vacuum.

With the engine OFF, brake pedal depressed enough times to release all vacuum - while holding pedal down, start the engine. The pedal SHOULD drop.

If the pedal goes all the way to the floor, the booster is working, the MC is working. but you DO have a problem.

It sounds like one of two possible problems. Either the MC piston diameter is too small or the pedal-to-booster rod is mounted too high on the pedal arm.