What oil temperature is your boat running? I have been running around 220-230. With hard runs and just cruising. Some say this is too high and others say its fine. I am running 540s with 420 mega blowers.

I am running the same temps under the same conditions. Mostly cruising with an occasional WO run. I have a NA 540.
In my opinion, those are good temps.

I agree... those are good numbers. You want your oil to be over the boiling point of water so that you don't get condensation in your oil causing a "milk shake" effect.

Some people say that is good and others say it is bad. Just trying to find out what is good or bad.

Cruise temps are about 220, hard extended runs temps rise to 260 (measured before cooler) 468" 671's Superchillers 8 lbs boost. Seems to work real well. Currently have close to 300 trouble free hrs on this set up. Recently switched to Mobil 1 15-50. Just bought M-1 V-Twin for the next change.

Oil reaches it maximum lubricity at 200 degrees f. Regular old dinosaur oil doesn't start to break down until closer to 300 degrees. Cruising at 220 and peaks of 260 is good. Check the oil on an air cooled motorcycle without an oil cooler.... They reach a scorching 350 and higher. Hot enough to deep fry chicken..

Is there any trick to getting oil temps above 200? Is this dependent on the type of oil used and/or the way you run? It seems difficult for me to achieve those temps.

Perfect. Your lucky.

been wondering the same thing myself; temp runs at 200-210 at cruise going up to 250-260 with harder running

Oil thermostat.

Also, sometimes using a crossover system instead of regular recirculating pump can cause this 'hard to get to proper oil temp' on some applications.