Heater shut off valve

[MD Mopar]

Does it really matter what hose you put a shut off valve on my heater hose? Just want to keep the cabin cool during the summer.

 

[Bigal75]

I would say on the inlet side. Why have hot coolant circulating in the heater core.

 

[MD Mopar]

so which connection on the water pump (front or rear). I guess the inlet on the firewall is the one to the far right on my 65 plymouth Bel II with 440.

 

[Bigal75]

I'm not 100% sure. I thought it was the left hand inlet on the firewall.