jchevy

What heater control Valves are you guys using for your A Body LS swaps. The 74781 valve that I bought works backwards from the way I need it to. The valve needs vacuum applied to bypass the heater core. The Cutlass heater control work backwards from this, when vacuum is applied the coolant flows thru the core.

Is there another valve that is similar that works backwards from the 74781 valve?

jimmyg

Use a 4 way mixer valve from a suburban . The thermostat on an ls needs the flow to operate properly. I've been thru this in my 83 cutlass / ls swap. The 4 way stops flow to heater core , then loops it back to motor. You need one from a 1998 or so suburban

jchevy

That is the valve that I currently have and it works backwards from the way I need it to. I need the valve to bypass the core with no vacuum applied.

jimmyg

Try switching the hoses around?

jchevy

I cant seem to visualize a way to do it with the different diameter hoses.