What temp thermostat would "the experts" recommend in a mild (433 hp) 385 sbc with aluminum heads and freshwater cooling. Alpha drive so no sea-water pump just water from Alpha pump. Currently running a 160 but getting a lot of steam from exhaust at most throttle positions off idle. Previous motor with iron head setup stuck an exhaust valve and motor showed signs of running hot, so just wondering if I should go to a 120 / 140 or some other setup. Temp gauge seems to get to 160 and stay there even on long 15-20 minute full throttle runs, so I believe I'm getting enough water. Also need to add an engine oil cooler over the winter as we are running longer river runs now with the boat. Component advice there would be great as well.

Thanks

I use 140's but the water gets warm around here and I like running hard.

Are your exhaust manifolds ok? Cracks can lead to exhaust valve issues like your previous motor.

If the manifolds are fine I think you are solving a problem that doesn't exist. 160 should be fine.

manifolds are almost new and pressure tested fine when new motor went in in June. Other motor setup did have higher dynamic compression due to tighter cam, so this could have caused the higher combustion chamber heat as well. I don't think I have a problem, just trying to prevent bigger problems if a cooler thermostat is recommended by those with more experience. this motor is only my 2nd marine build so just looking for all the advice I can get. Thanks for the recommendations.

How cold is your water? Steam is normal in cold water as long as you have proper water flow, and going to a cooler thermostat will make it more difficult to burn out any condensation in the oil.

Don’t see an issue with your water temp. Also suggest for you rig a 218 degree oil thermostat to cook off the water condensation in the oil. Hardin sells oil thermostats.