hi I replaced all vacuum lines and the A/C and Heat moved properly from defrost to vent to floor etc
The problem is I don’t get any heat
i replaced the heater valve on the back of the intake manifold but I dont think it is opening
Any ideas would be much appreciated
Thanks
BR

 

Comfortron or manual control A/C?

Assuming it's manual control... Check the heater inlet and return hoses with engine at operating temp. Both should be hot and within a few degrees of each other.

If the inlet hose is cold between the water valve and heater core it means the water valve is either not functioning or may be the wrong one for application. Pull the vacuum hose and see if things heat up. If so, get the correct water valve.

If inlet hose is hot but return hose isn't, you have a plugged heater core. A backflush is in order.

If both hoses are hot but no heat in the car, either the temperature cable is bad or one of the vacuum motor diaphrams is bad.

Comfortron is a whole 'nother ball game. Consult your factory CSM.

 

Some heater control valves work opposite make sure you have the correct one...

 

The 1966 uses a heater control valve that is normally closed and opens when vacuum is applied. Most catalogs incorrectly show the later normally open valves for early applications.