Whats everyones opinion??

In Mi. I would run them up to 600 HP NA.

I've had motors both ways. 800 sc's then got rid of the B&M blowers for BDS 10-71's without thermos still ran fine. What is the main thing is what kind of lifters are in the motors. Flat tappets will wipe a lobe of the cam rollers are alot more forgiving. Cold oil is a problem for the main & rod bearings but you cqn use 10-40 oil to help with that. But the cam doesn't see near the heat & flat tappets will kill the cam since it's feed secondary after all the mains & rods. Valve springs & valves love cold oil though thats why we use valve spring squirters & coolers on our Nascar engines. My 2 cents & exprience.

The motors are hyd rollers, close to 600 hp. Been running with thermostats(with multiple holes drilled in) for the last couple of years. Pulled them out last night, going to try it tomorrow without them.

Keep us posted on your results. I have run both ways in the past but I am now running a thermostat with multiple holes as you mentioned. When I was not running one I was attempting to help an oil temp issue by increasing water flow while still maintaining "some" heat in the block.

I would say it depends on the engine. As long as the engine can maintain good oil temps and runs the same way consistently in varying lake water temps, then I'd say fine. You should still run some kind of restrictor plate, IMO, to avoid steam pockets.