Gage

My 69 w AC had one but my 72 does not I noticed in the book that 72-75s don't???? Anyone know why?? To me it made sense to block the heater core off when AC in "MAX" position, actually it makes even more sense to block heater core off when ac controller is in any position except heater or defrost.

comp

if there is no flow threw the heater core it's fine, i like the heater hooked up
incase it runs a little hot the heater will pull extra heat out in a emergency

maint1

When I put new heater hoses on this winter I put a manual shut off in the heater hose. Here in Vegas I use the air more than the heat but in the winter it's still there. Only disadvantage I can see is that if you want heat you manually have to raise the hood and open the valve. Got the shut off at NAPA auto parts.

Gage

yeah, so switch to heater or defrost and hot water valve opens if you need extra cooling. I was thinking of splicing tan stripe vac hose, which I believe has vacuum when every setting except heat and defrost , and running a vac hose to shutoff switch. Any AC/heating experts feel free to chime in here

NHvette

I have/had a manual valve, too. That's what I would do.
Turn it off in the warm months.
Actually ... valves in both hoses can help.

Home Depot ... 1/2" stainless ball valve.

RMS73

I put a vacuum operated valve in my supply side hose. To open the valve and get heat I just pull down on the vacuum valve below the steering wheel.
Roger

munday

AC?????!?!?!?! whats that... A heater????!!! That's why i have long tube headers...i don't need no stinking heater :smiliedrool:

Gage

Yes, I had long tube headers on my 69 BB. I definitely never had to turn on the heater with that car, as my feet were quite comfortable on the coldest days. Wasn't much fun in the Texas summer though, as you should know. They were great until some guy hit me and in the accident it pushed the footwells into the headers and the thinking started to catch on fire...fiberglass is flammable you know...

Shrike

I would actually completely disconnect the heater core during the summer. Just run a hose from the intake to the water pump, and connect the heater hoses to themselves.