Fresh air plenum valve in cowl diaphragm P/N

[crustysarge]

While sealing some minor leaks in the cowl area I found the fresh air plenum valve to be broke off at the shaft from the vacuum diaphragm. I am attempting a JB Weld repair and also found the diaphragm is bad. Does anybody have a P/N for the diaphragm, maybe a Autozone number so I can consolidate with a upcoming mail order I have to make. Also is the plenum valve available anywhere?

Now, I assume this thing opens when you turn the heat on to allow air in?