[67_Bird]

My car is a weekend driver. I have no need for a heater. Yes, I understand the heater core fan cool off ability. What do I need to block off the rear passenger head port and the water pump heater hose connection on a 67 400? I currently just have rubber caps clamped on but don’t want to risk them popping off/leaking.

[Elarson]

One option would be to run a hose directly between head and water pump without the detour to the heater core.

Eric

[67_Bird]

Originally Posted by Elarson

One option would be to run a hose directly between head and water pump without the detour to the heater core.

Eric

True, trying to avoid/eliminate unnecessary lines wires and hoses though for a cleaner look.

[Formulas]

i have pipe tapped / plugged the timing cover and used a regular freese plug on the head after poping out the heater fitting

[Don 79 TA]

just use a good quality cap and check them regularly
i haven't had issues
the "Help" ones i changed yearly/every other year because i saw what appeared to be some dry rotting on them, and just swapped them as a precaution
i bought a real nice one for the timing cover i think off Amazon, forgot who made it, but is super nice, might have been Summit, don't recall
many of the import guys liked it so i gave it a shot
3 years, still in great shape

[JLMounce]

If you're looking to completely delete the heater all together, I would recommend re-routing the coolant loop.

From both of the heads at the back, to a Y that travels under the intake manifold and dumps fluid into the water cross-over. Then plug the inlet at the water pump.

This will help even out your head temps and dump the hot water/coolant back into the system without bypassing the radiator.

While the heater core can help shed some heat from the system, it only does so when it has air moving over it. All other times, it actually works against vehicle cooling, because the factory circuit puts the hot water back into the water pump, bypassing the radiator. There are reasons why the factory did this, but if you never run the vehicle in cold weather, those reasons no longer apply.

[dataway]

69 A bodies used a water control valve in the heater circuit that prevents re-circulation doesn't it? Level of heat was controlled by how much water the valve allowed through the heater core .. pretty much the same as capping the hoses ... I think.

I've heard it was done to help the AC work better by keeping heated engine coolant out of the interior HVAC case when it was not needed. Makes me wonder if a manual valve in the heater core supply line would help out the AC performance on models that's didn't use the water control valve.

[lust4speed]

After seeing a new plug disintegrate and fall apart on a rebuilt engine that was sitting waiting for completion of the body restoration I swore I'd never use them again. A short piece of heater hose with an appropriate 5/8" diameter plug of some sort in the end will basically last forever. Not that pretty, but you don't have to worry about your coolant purging out as you go down the highway.

[chuckies76ta]

Originally Posted by 67_Bird

True, trying to avoid/eliminate unnecessary lines wires and hoses though for a cleaner look.

So the only coolant your moving around when starting the engine from cold is through the bypass.
I'm curious, does your engine come up to temperature fairly quickly before thermostat opens?

[lust4speed]

Originally Posted by dataway

...Makes me wonder if a manual valve in the heater core supply line would help out the AC performance on models that's didn't use the water control valve.

I installed a manual shutoff valve in the hose going to the heater core on my '67 GTO that had factory AC. Turned the valve off in early Summer and back on when things cooled off. Some of my friends had two valves and also blocked the hose out of the core to stop radiant heat going back up the hose. I tested the heat of the return hose and it stayed pretty cool when the main valve was off. Heater doors on the early cars definitely leaked hot air even after replacing the foam around the edges of the doors.

[dataway]

Good to know, might have to consider that ... doesn't help the interior temps to have a pretty much uninsulated 180 degree chunk of metal under the dash, and adjoined to the same passages used by the AC.

[67_Bird]

Originally Posted by chuckies76ta

So the only coolant your moving around when starting the engine from cold is through the bypass.
I'm curious, does your engine come up to temperature fairly quickly before thermostat opens?

Takes about 8-10 minutes to reach 180 at idle