You are talking about a header evac system. You can get weld in bungs and the 1-way valve from Scummit and Jegs all day long. You just run rubber hose from the VC to each collector.
Two things: As said before, it has to be revved pretty high to suck the vapors out and if you putt around town or only briefly visit the upper end of your tac, you're going to leak more than you do now. AND you will need and free flowing exhaust, the vapors in PVC systems get re-burned, on an evac system that raw crank case fumes and gas goes to your muffs. These system will cake up a muff if it isn't a straight through design.
Remember, header evac systems are best used on drag and hot street cars. For a street or street/strip car a PVC is best.