I used the Indigo kit since there was not room on the front (flywheel side) of the engine for the Moyer pump. The Indigo kit has a manual thermostat valve that allows a range of about 40 degrees in temperature. With the valve set for full hot, my engine runs about 180 under load at around 1500-1700 RPM. Sounds like yours is running a little too hot. I flushed my engine with muriatic acid several times to remove most of the crud but also removed the water cover plate and physically scraped out a bunch of sludge that the acid did not remove. You may also have a restriction in your exhaust elbow arrangement, depending on what style you have. Bottom line, I'd be concerned at temperatures over 180.

Eric