92 Sierra question about power brakes...

I have a sierra and i am installing a whole new wire harness from painless. The question is how does the brake system work on these trucks? i am not too schooled on brakes for some reason. The truck was a 4.3 but now im putting a 350 carbed motor in it and im re-wiring it because when i bought it the wiring was a nightmare. Does the master cylinder work off of vaccum or power or can i just bleed the brakes and drive it the way it sits? NO IDEA! lol help please...

Not %100 because its been so long since I had my 89 but I thought it was vacuum.  Either way you will not mess with your wiring because if it's not vac it will be hydraulic and that comes off your power steering.

Yea i hope not i just need to figure it out before i start driving it.. i went to a junkyard the other day and there was a hose that went from the master and bolted to the intake manifold on a newer 96 silverado but that one was fuel injected.. i need help..

anyone else?