Big block A-body cooling

Wondering what you guys are running to keep them big block A-bodies cool.

The car in a 1971 Dodge Demon. It hasn't been driven much in the last 5 years but it always ran hot. I couldn't keep it under 210.It has a mild 383 built years ago but always ran hot. It has a cast passengers side drop water pump housing, 26" E-body radiator and a belt driven flex fan.

Now that I have an itch to drive it every day I want to get it right. I have since moved south to Texas where I'm going to need all the cooling I can get with hot ambient temps.

Doing some research I noticed there were two different water pump housings. We had to run the passengers side drop to get a timing mark tab. That is my first idea if the coolant is even flowing correctly. My lower hose feeds the bottom tank and upper to the t-stat neck. I still have heater core connected but not against removing if it helps with cooling.

Another "if" I have is we never opened the radiator core up for the 26" e-body radiator. I did have it steam cleaned twice with no change.

I know this thing can and should run cooler. timing had no effect and honestly cant nor think the carbs we ran did anything for the issue. T-stat is a 180 also.

I'm prepared to upgrade to aluminum radiator and electric fan but hate to have same results and it just being a issue with flow. I've tried several different gauges too.

If you have any input on the matter I appreciate it. Also what setup you're running to keep it under 200.

Flex fans are usually a bad idea. For a street car the trick is to copy what the factory did on the cars with max cooling.

Big radiator, shroud, big clutch fan, over drive water pump, 8 vane water pump, etc.

Flip thru a master parts book sometime and look at the cooling parts used for taxi, cop cars and station wagons. That will show you what you need to do.

What Andy said...


And, a good 4 core copper/brass with a proper shroud and fan clutch setup should cool it well. No need to disconnect your heater either.

Not having the core support opened up to the size of the radiator is a bit of a waste though, should take advantage of the radiator size I would say.

Electric fans are nice in cases, but you need a charging system upgraded to go with it. And a good fan clutch and shroud package on a large radiator should work great anyways..

That's what I did. If you look through my build, the part numbers are listed somewhere. IIRC I used a Polara rad, Roadrunner fan shroud and a Jag fan clutch.
I hope this helps. I haven't finnished the build to see if it works.
Copper

More info needed: that eng always ran hot in that car or in the car it came out of also. any idea if the rad is partly plugged. not usually critical is pulley ratio/# of vanes but post what you have. shroud or no shroud. fan distance from rad. fan type (did you say flex which ain't good). #1 #1 does it run hot stoplight to stoplight or out on the highway (or both). I'm assuming mixture is OK (no vac leaks) & hopefully no combustion leaks and you said timing is OK. stat opening all the way. pump nipple side does not matter. Holler when you can

Thanks for the replies everyone.

Car ran hot all the time. No vacuum leaks. Again its been a while since we messed with it really trying to get a good direction to go. I have a shroud and fan is spaced up close. I had radiator flushed processionally twice. Doesnt mean its not restricted but it came out of a running e-body. Thats why i was think of replacing it the unknown... Deffinitly going to lose the flex and open the core... as far as pulley size. I remember we had to hunt for a pulley, weather its over or under driven not sure. Ill measure them later.

Get a laser heat gun, aim at the bottom, middle and top of rad. Check hoses waterpump, just about everywhere water flows. Bottom of rad. should be cooler than the other spots. 210 is not bad but should be around 170-90. A buddy has a 65 Hemi(472 iron) with no shroud,4 blade fan and it never goes over 170, sounds like you have some issues in the engine, maybe cam retarded a lot, not a clean combustion, timing off, what do the plugs look like?
One thing I foggot to add, the engine will not run cooler than what the temp. is at bottom of rad. So if your rad says 190 at the bottom, it is circulating to fast or stopped up.

You might also want to check the waterpump vanes to back of waterpumphousing distance.
Ideally you want the vanes to 'just' touch the housing if mocked up without a gasket in place.
Also, more vanes means more water pumping action.

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I had radiator flushed processionally twice. Doesnt mean its not restricted but it came out of a running e-body.

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I have never had good results with flushes or ultrasonic cleanings. I prefer to have the radiator's core rodded out that way you know each tube will flow. So start with a good radiator and follow what the others have said.