they both need a vac source. I use one of these on my supercharged GMC
http://www.ebay.com/itm/OBX-Universal-Vacuum-Distribution-Block-3-Ports-/181168469661?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a2e7b769d&vxp=mtrI installed it between the hose from the intake manifold and the brake booster. So it would intake mani to the vac block, out to the booster. No issues. would want to install a air check valve on the hose between the block and brake booster to keep boost out of the brake booster