On Project89's old thread, he said "the only one mod i had to do was install a check valve on the heater control valve line, the line that controls the vents, without on it would pop the hoses off, its like a 79 cent part form the auto parts store". can someone show me what piece he put in, and where?

 

A one way check valve. Also you can use fish tank one way valves. We used to use those to trick boost reference on maps in the early days.
Anyways. It should be installed on the back of the intake mani. There is a line that goes through the wiring harness I believe ( been years, I don't have any now). You want vacuum open under vacuum. Also if using the fish tank type, oil them up. WD-40 or whatever. They work better that way. And the they part is you may need more then one.