Going to power brakes on a 76 c10

[ttjordan25]

Ok. my truck had manual brakes. I am wanting to convert to power. The truck had a combonatin valve bolted to one of the front crossmembers, which I assume helped control the front and rear brakes from the master cycl.. My question is when I switch to power brakes do I still need that combo valve or will the porportion valve that is on the new master cycl/brake booster take its place? Hopefully im question is clear.. thanks!