305 tbi. my heater core was bypassed and I'm correcting that now. I'm missing one of the hoses that connects to the heater control valve and im not sure where it goes. the two on the fire wall are there as is the vacuum line the last is missing. I believe it goes to the manifold. the thermostat housing has two caps on it. so that's a possibility. can anyone give me a heads up and/or a shot of yours hooked up?

 

Rear of the intake manifold by the distributor to the side of the valve. Rear of the valve goes back to the heater core and down to the hard line on the frame rail.

 

rear of the manifold? alright I will look for it thanks man.