I'm using the following heater valve on my two hoses that run from and to the heater/engine -
https://www.oldairproducts.com/produ...ve-kit-50-1555
Say's "Special design diverts coolant directly to the engine, away from heater core, when in the off position to reduce excess heat inside the vehicle"
In my minds eye that would mean I shouldn't need a bypass hose on my Vortec head style engine? What do you think?