Good friend has a 70 Dodge Charger with a 440 bored 60 over. The heating issues only surface when it's idling or driving slowly in traffic.

As long as it's going down the road it doesn't get hot. It has a big aluminum radiator and twin electric fans with shroud.

He has checked the timing and made sure there is no air in the system. Even took it to a local mechanic who confirmed all that but said if you let it sit and idle it will get hot. He even used another external fan to try to help cool it.

The engine was rebuilt by a local machine shop and he is concerned that maybe the head gaskets were installed incorrectly and maybe the water jackets are partially blocked. Anyone had any experience with this?

Any help is greatly appreciated. He has even considered having the original 383 rebuilt and reinstall it. He would like to put air conditioning on it and he knows that will make it even harder to cool.

sounds typical fo big block ford.these engines must have a 4 core radiator with all the fins you can shck in there.im not a mopar guy so not sure about gaskets.

Maybe an electric WP could help with this problem.

Put a smaller pulley on the water pump, not circulating fast enough.

quote:

Originally posted by Bill Koski:
Put a smaller pulley on the water pump, not circulating fast enough.

That would be my first try.....and/or a high volume water pump

My 67 R/T does the same thing its original so don't want to change the radiator. It's not real bad but on a hot day the temps will becoming concerning at a long red light but go right back to normal when I start moving. - May try the smaller pulley.

Which water pump does he have? The 5 or the 8 blade?




Dam, those are big. LOL

Also, the ACDELCO 252587 pump has a plate behind the impeller that doesn't allow the water to "paddle" at low speeds. It was on the high HP engines.

I'd dump the electric fans and go to the biggest belt driven fan he can get with a shroud, and high volume water pump if available...

Something to consider...what's the timing set at? It can overheat if the timing is too low at idle...might need some advance....

Timing..My guess is it does not have enough initial timing in it. Why it has issues idling and low RPM assuming it has a vacuum advance.

Has the Block been" Filled" ? even partially ?
These Big Blocks can easily develop circulatory issues if the grout or filler blocks flow between cylinders and head bolt casting bosses.
If huge radiators arent eliminating the issue then there is usually some circulation issue.
Plenty of 440's back in the day in Police cars that would sit there all day and idle. Same with most of the Mopar performance line up back then Good Fan shroud , viscous drive fan, Belt driven water pump, Stock Radiators with A/T cooler loop in the bottom tank as well..That stock cooling system was adequate for about 450 H.P..

Make sure you don't have any holes in the front core support that would allow the hot air in the engine compartment to get recycled back through the front of the Rad.

Rad should also be sealed to the core support.

I agree with speeding up the watr pump with a smaller pulley.
Also take the thermostat out if you have one installed.