What engine temp do you guys run your engines at. I have always run mine with a gutted t-stat and am about 120 degrees but am now thinking that maybe piston and rings weren't getting up to temp and poss cause for blow by?

think this is engine dependent...but my small blocks run at 175F-185F. i have heard other engines running at 120F. others can chime in.

A working Thermostat is a good thing. You really want to be around 150* and up. Although it's hard to get up to 190's because a constant source of Cold water doesn't like to get hot. most parts in your engine are made to run in the 190's, but thats hard to do in a boat....

I would say 150+ My big block runs between 150 (idle) and 165-170 (on plane). Climbing over 200 on a big block or about 210 on a small block is cause for concern in regards to internals. But if you go over 180, you probably have water pump, impeller, or blockage issues

Thanks for the info.