So my latest project is running a little warm. I took it to Ron Davis Radiators here in Glendale Az. And they told me a had the wrong pullet set-up. Their recommendation was a 7in Crank pulley & a 5in water pump pulley. Not too big a deal, in theory, but I can't seem to find what I need. It's kind of looking for 2 particular trees in a HUGE forest.
So does anyone have a part number for such pulleys that will fit a Hemi?
I tried various aftermarket companies and a few come close, but not quite. Any help/suggestion would be a huge help.....

Hemis had overdriven waterpump pulleys from the factory.
Maybe March or someone else makes the right pulley?

I dont think you need to be overdriven that much. what pulley dia do you have now? overheats at idle or WOT or cruising above 40 MPH or stoplight to stoplight? do you have a schroud? what # of fan blades? how far into the schroud is the fan if you have a schroud? how far is the fan from the rad if no schroud? timing/mixture in the ballpark? when did the problem start? any recent part changes/adjustments preceding the onset. what offset of pulleys do you need.

I like the sound of the 7" crank pulley, and the 5'' water pump pulley. All my Mopars run cooler with faster water pump speeds. I've never been a fan of the water going thru the radiator slow so it has time to transfer the heat. I have never had a problem with cavitation either.

Problem is, you have to experiment with different pulleys to find the right combo. $$$$$$$$$

Pulleys aren't awfully hard to find; main thing is getting the right depth, which can also be adjusted with spacers. You might search "Mopar pulley" on Ebay, as I've done. Water pump pulleys seem to be interchangeable between all Mopars as far as bolt pattern. Another measurement that matters is where the OD is measured: at the base of the V, or the outer edge.

Well right now I'm running a Griffin 26" radiator, 2 SPAL 12" elec fans with a shroud & the fan's about 1/4in into the shroud & Evans coolant. The pulleys are 6in on the crank & 6 1/2 on the water pump.
The guys at March told me to divide the crank pulley diameter by the water pump pulley diameter to get the ratio. Doing that with my current set-up I get 1.08. If I use what Ron Davis suggest, 7in & 5in., I get 1.40---considerably different & better.
Their theory is to get the water flowing faster through the system so as not to "soak" the water with too much heat, making it more difficult to cool. The set-up is in an A-body so space is at a premium.
As mentioned, most pulley set-ups I see have the crank pulley smaller than the water pump, but I think for a higher horsepower set-up I may actually need to "speed things up" as they suggested.

1.40 isn't unreasonable. The factory ratio for the hemi was 1.2

Makes you wonder how many issues are caused by underdrive crank pulleys.

You still haven't told us when it over heats. There could be a very simple solution to this problem once you know where to look for the culprit
Better than throwing parts at it

Gus

Depends on the year; prior to '69 the Hemi pulley ratio was .95-1 (same as the non-A/C V8's) but in '69 they went to a 1.20-1 overdrive. The other engines went to a 1.40-1 overdrive in '69. So there are no factory Hemi pulleys that would provide a 40% overdrive.

And, before considering overdrive pulleys, you have to know the vane size in the W/P.

with smaller, over driven water pump pulley the fan speed is also faster drawing more air across the radiator.

Bouchillon can likely fix you up. The ~ 7" crank pulley is pretty typical as stock. They also have a big selection of WP pulleys and diagrams to help choose.

I called and talked to them to get mine sorted out after engine swap. I think my WP pulley is around 5.75". Something like that would get you pretty good overdrive with a 7" crank pulley.

FWIW I run a 6.25 AL crank pulley and the approx 5.75 fan pulley for something like 7% overdrive. With a high volume water pump it cools a 496 with AC very nicely. The radiator is a Mancini 26" aluminum "muscle car" radiator with matching shroud.

http://www.bouchillonperformance.com/

Which is part of the reason that was an AC thing, more air across the condenser too.

Makes no difference---at idle after about 15-20 mins. or after driving about 20-30 mins. I'm pushing over 200-210 degrees.

210° isn't worth worrying about if it never gets much hotter than that. Here's the specs on the '69 and later Hemi pulleys.

In terms of temps, warming up a little when stopped is pretty typical. OK as long as it does not get too hot.

Warming up while driving would be more concerning to me. With good airflow at speed I would expect the temps to hold just over T stat temp with a healthy system. Speeding up the water pump may help but I wonder if there is another problem. Radiator not sufficient or maybe water pump not sufficient? Did Glendale sell you the radiator?

Does it have a mechanical fan or just the 2 spal electrics.

Just the electric fans. When I initially went to Griffin they said those, coupled with the Milodon W.P. would work. My concern isn't just the rapid warm-up at idle but that even at speed the temp wants to climb.

As I sa, currently the crank pulley is 6in. Si even just finding a 5in W.P. pulley would or should be an asset. I just can't seem to find one. Bouchillon & CVR said they didn't have anything near that.

needs a mechanical fan IMO.

I'm kind of thinking that too but from their perspective, and they do this stuff for a living, the elec. fans will give consistent airflow while the mech. one is naturally dependent on idle speed. Lower RPMS=less air= more heat.

The current radiator is a Griffin unit. Other than a blown head gasket, which would be pretty evident, I can't think what else could or would be the issue---oil & coolant look normal, the car runs well and there's no weird noises or anything else coming from the engine. And I agree---the engine should be in the 180-195 degree range at speed but it's not. A 5 mile trip in Summer weather & I'm already at 195 & climbing.