The four port valve upgrade from the HCV is not a "requirement". As Artgirl said, you can run fluid through the heater core at all times and all will work fine, and this will solve the thermostat issue. However, the downside is that the Vintage air system was designed to use the HCV(supplied Heater Control Valve) to shut off the flow of coolant when the heater portion of the HVAC unit was not being used. What will happen to temps and efficiencies of the Vintage Air unit when in "max AC" mode without any valve being used? I really don't know. Maybe Vintage Air can answer that?
The solution offered just keeps the Vintage Air system operating as designed by it's manufacturer, and also changes things a little so that the GM thermostat is operated as GM designed it as well. So the 4 port valve essentially just makes everything work as intended by the combination of manufacturers of both the AC unit and the engine.
Use it, don't use it, plumb it differently, whatever. As the saying goes, "there is more than one way to skin a cat". If you absolutely know what you are doing and have considered all the potential consequences of changing things, then no problem. Build what you will. I offer this kit simply so that builders can make this stuff work as a "no brainer".
And not trying to bash or demean anyone in any way. I am one of those guys that can't seem to leave well enough alone whenever I get something. I take it apart, I look at it for long periods of time, and I try and see if I can come up with a simplier, easier, cheaper, or better way, so I fully understand what you are saying and where you are coming from.
If you do go your route of hooking into the lines that run through the tunnel instead of running lines to the thermostat housing area of the water pump, you will need to make sure that there is continuous flow to both sides of the thermostat. If all else fails, then just run a U tube connecting the inlet and outlet at the thermostat where the Vette heater hoses originally attached.
However, if you want to also address the head steam vent issue, then putting a Header Tank kit on will address this AND allow water to flow to both sides of the thermostat. You can then put the 4 port valve anywhere you like before the heater core, or just use the HCV and just stop flow entirely in the hook up lines for the heater circuit.
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Originally Posted by crash
The four port valve upgrade from the HCV is not a "requirement". As Artgirl said, you can run fluid through the heater core at all times and all will work fine, and this will solve the thermostat issue. However, the downside is that the Vintage air system was designed to use the HCV(supplied Heater Control Valve) to shut off the flow of coolant when the heater portion of the HVAC unit was not being used. What will happen to temps and efficiencies of the Vintage Air unit when in "max AC" mode without any valve being used? I really don't know. Maybe Vintage Air can answer that?
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