Fixed cooling fans for a 340

Is your Hayden clutch Thermostatically controlled? or just a viscous coupling?
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I went to the Ford Dealer and got me a HD T-clutch off an early 2000s Pick-up truck, that was still CW driven same as my Mopar 367.
I run that with my big 7-blader, that I pulled off my old '75 Dart 318/auto with A/C. Yeah the one with the angled tips.
I run a 195 stat, and the fan cuts in/out to keep the coolant at 205 to 207, no matter how I drive it.
From the driver's seat, I never hear the fan, lol.

With my dash-mounted dial-back timing module, I can run Idle-timing anywhere between 5 and 20 degrees, depending on desired groundspeed with a manual-trans. Five degrees gets me 4mph@550rpm in gear, for parading.
But,
I also run up to 22* in the Vcan, depending on the throttle-opening. By 2000rpm/14mph, that typically is 44* of cruise-timing.
And I should mention, that my 11/1, alloy-headed, 367HO will happily idle at 5* in gear and parading at 4 mph, for as long as I want it to. To achieve that, my hypereutectic pistons were installed a lil loose, and the top ring gaps adjusted looser than the KB specs. That made all the difference; and is hands down, the best thing I ever did for my formerly tight and hot-running engine. Nothing worked until I filed those rings. Afterwards, I couldn't hardly get her warmed up!

Best of luck to you.
In 2004, that 367 went 93 in the Eighth.
Engine now has over 100,000miles on her and still going strong.