brake pedal goes to the floor

[vestas1]

hello everyone, I have a quick question it may seem dumb but i can not find any info on this topic so any help would be really appreciated, I have a 1969 ford f250 and i changed the brake booster and master cylinder from a 1987 ford f250 and i can not find any info on which port is for the front and for the back brakes. Some say the rear one is for the front and the front one is for back but i also read the other way around. Please nay help is appreciated, Thank you.