Re-post from earlier with a different question...

This is an original Air (removed) 71 Big Block with the black cylindrical expansion tank on the inner fender.

The tank has 4 nipples - radiator, overflow, water pump, and heater core. Also the main heater hose has the valve with small vacuum hose - not sure if this is an issue or not.

Option 1. Remove both Heater Hoses. Plug Manifold. Cap off expansion tank heater core nipple.

Option 2. Remove both Heater Hoses. Run new hose directly from Manifold to expansion tank heater core nipple. A true Bypass.

Will Option 1 cause increased engine temp?
Thoughts??

Many thanks!
Mike

 

I don't have a big block but I do have my heater core bypassed. I used a pipe plug in the water pump and one in the intake manifold. No hoses required. No problems.

 

When you look at the water pump. Your heater hose is above the larger radiator hose. These are the cold water inlets to the water pump impellers. The spinning impellers force water out the back of the pumps throught the block up through the heads on the return goose neck.

The vacuum valve fails open. That's why you get hot air out of the air vents on our old vettes when these tiny vacuum lines crack and decay with age. Hot water is circulating through the heater core.

The heater core with any flow is removing additional heat from the motor.

Instead of blocking of or dissabling the heater core rubber lines. People have installed simple 90 degree ball valves on either the supply or return. For summer shut off.

Vettes are bottom breathers. To increase air flow the bottom chin spoiler can be added to. It does two functions. By daming the air passing under the car your forcing more air up and into the radiator and it is creating a partial vacuum under your car behind the radiator pulling the air through. For years i had rivited a small stiff 4 inch or so piece of stiff rubber across the front of the small stock chin spoiler and rounded trimmed it for looks. It worked like a champ. As power went up i got rid of the heavy T-clutch fan and used the big bladed SS flex steel fan and the stock shroud. I also installed 40% higher flowing pumps and high flow 180 degree thermostats. The 79 L-82 stock shroud also had a large fan for A/C use or when the temp went up it kicked on.

I use a shut off. In answer to your question. a correctly improved system should not require the heater core for addition BTU removal

 

If your getting rid of the heater and hoses I'd just use brass or steel pip glugs in the water pump and manifold. Get rid of the stock ugly expansion tank and run a trick aftermarket tank of the radiator puke line.