brake question

[jht3rd]

Hello guys,
I'm new to the forum and a new owner of a 68 C10.
Any ways When I bought the truck it came with an old booster and brackets
to covert to power brakes. It has a little rod that connects on the top bolt of
were the booster bolts to the bracket and a brace that bolts on were the master goes. Does this mean its a 3/4 ton setup ? also my firewall has no mounting holes for these brackets. Do i just drill a hole and run a bolt through? The reason I ask all of this I'm having braking trouble. I used the
rod that goes from the booster to the brake pedal from the booster and brackets that came with the truck.I got a new booster and master cyclinder from a local parts store, I told them for a 68 1/2 ton. Was this right considering the brackets I have? Now after mounting all of this to the stock proportioning valve that was already on the truck, it seems like the pedal goes down half way before it starts doing any thing. A friend and I bled all the air out. Any thoughts?
Thanks,
jht3rd