Kent mosby said

I have just read the rather lengthy and well detailed thread on overheating and yet I still have some questions and did not want to hijack that thread.
I have a 1973 plymouth scamp with a 512 that always ran under 200* while moving. This past weekend I went to a car show Car d'Lane and during the Friday cruise it was 90*. The cruise was more of a crawl. In about 30 minutes I travelled maybe a mile. My temp steadily climbed to 251* according to the sniper readout. Nothing blew and I pulled off the route. As soon as I got it on the road at about 35 mph it dropped to 205 within a couple miles. I obviously need to correct this issue asap.
My cooling specs are.
180* Mr. Gasket 4367 high flow, high performance thermostat
Mopar 7 blade fan. crank to fan pulley ratio,, .95:1
Griffin performance 8-00038 26.5x18 2 row with 1.25 inch tubes
3871088 mopar 8 blade water pump.
7 psi radiator cap
Shroud, Homemade by me but looks appropriate,,, let me know
There is a 10x12 inch trans cooler in front of the radiator.

Since the radiator cools appropriately when the car is moving and at the race track, I assume that I have enough radiator but not enough coolant and/or air flow at low speed or idle. Correct???
Now for the corrective measures. Our race track closed so I do not need a cooling system for that purpose. I am now making the car a street/show driver. Slow speed cooling is a must.

My thoughts to improve things are that I could overdrive the water pump by changing pulleys?? And/or get a different one but this one is supposed to be good.

I could switch to electric fans controlled by the sniper efi but that would require that I change the alternator to a 90 amp from 60 and I would have to change the radiator as this one is 3 inches thick and it sticks out from the core support by an inch leaving only 2 inches from the water pump pulley to core.

I could get an electric water pump that may save some space. In AndyF's book he states that the electric pumps are ok for racing but will not keep up for street use. Any experience on this? Good or bad idea?

I could change the thermostat to a 160 milodon high flow model.

Anyone use a pusher fan in addition to this setup for street use??

I tried to gather as much info as possible before posting but I may have missed something. What would you do to correct the slow speed cooling issue?View attachment 1715754294 View attachment 1715754295 View attachment 1715754296 View attachment 1715754297 View attachment 1715754298

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yellow rose said

You can NOT underdrive the pump that far. You have a kick *** radiator. As RRR said, you NEED a Flowkooler pump and some overdriven pulleys. And a Stewart Components thermostat. There is nothing like it on the market. These are the old Robert Shaw thermostats.

You’ve got most of what you need with the radiator. Now you need a couple of little thangs and you’ll be pooping in the tall cotton.

EDIT: I forgot to mention you need to throw the shroud away and use a spacer to get the fan about an inch away from the radiator. If you get it that close, you want need a shroud. It will be close enough to the radiator to pull plenty of air at idle (if you get the pump speed, and by mechanical connecting the fan speed up where it should be) to keep it cool at at high speeds the shroud won’t be packing air.

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