brake conversion HELP!!!!

[towrecker]

HELLO ,well i have been in the process of getting my 63 c-30 to stop not just slow down :-p well i walked into the local parts store around the counter and took a computer hostage and looked up every car or truck power brake booster i could think of that had power drum drum brakes and well i found a booster off a 69 chevy 1 ton that was close in design to mine ok i guess i should say i was looking for a big booster (a double ) well i ordered the thing and bought some line a plug a union and whatnot to split the system while i was at it got out the door for 105.00 not bad found setups online for 200.00 i got master and all ofcorse well i have a 69 c-10 hum lets look it over i thought it has set for years and has manual brakes well same master sure enough and drum drum but it has a block mounted to the master that the lines go through humm what does it do i think it might just be for the brake warning lite or is it some kind of residual pressure valve remember its a drum drum truck so i know its not a bias valve ok to my point what is it do i need it on my 63 c-30 or not heck i will jerk it right off the 69 if i need it just don't know for sure what it does edited by mod

thanks ,
jason

1963 c-30 wrecker
1965 c-10 custom
1969 c-10 custom grass killer !!