Which is best Thermostat and fan switch combo

[prayers1 153]

351 Cleveland stroked to 408, 515 hp. 
had a 180 T-stat and always ran 185-195 degrees. Long wait at light or racing it would run 205-210. Now switched to aluminum radiator and dual fans. What thermostat and fan combo should I use?

choices are:

195 or 180 thermostat

185 on / 165 off or 195 on / 175 off

[candoo 9]

210 is not hot and cause for concern. 220 plus is an issue. Had a cooling issue with my 393C and tried several things including dual fans. Dual fans worked at idle but restricted flow to much while running at highway speeds. Long story short I converted to a regular stat and installed a blocking plate (purchased via pantera forum). My issue was tuning and no stat I every bought completely blocked the bypass and I was always recirculating. I also put a restrictor in the heater hose to the core. All good now.

[RPM 1,190]

 

I think with either of those senders your fan will be running most of the time. If those are your only options go with the higher temp. 

[1969_Mach1 333]

I'd go with the lower temp thermostat.  Running the motor at higher temps increases the possibility of issues like pre-ignition (pinging).  Then retarding ignition timing to prevent or stop pre-ignition further increases operating temps.  Plus, if you get into a situation where the motor actually does overheat you have to worry about piston rings collapsing.  Maybe I'm old school, I don't know why some like to run motors in these old cars at high temps.  It won't be easy to keep a 515 hp motor cool in these small engine compartments.

[prayers1 153]

Candoo- are you referring to the by-pass restrictor plate?? There is also a blocking plate (circular disc) that goes in the block to stop the flow to the water pump outlet for the advance vacuum.
I have the by-pass, but had the wrong t-stat. That might of been my big issue for getting up there in temps. I ordered the correct one from TMeyer racing. What temp does your Cleveland run on an average?

it is a tight engine bay for my type of motor. Trying my best to figure this out.

 I agree that I’ll probably go with the 180 stat and 195 fan switch. I don’t mind keeping the temperature in the 180-190’s. Fans will probably never turn off, I really have  no other options beside what I said above

[ClubSport 29]

I use a single 16" SPAL heavy duty with a 180 thermostat and an Autocoolguy NB50 PWM controller : very good combo for my 351W - stable temperature 195/200 degrees even with outside air temp of 90-100 degrees