The 261 by-pass thermostat will definately not fit in your 235 housing. It seals in 2 places as opposed to one and comes with a separate interior gasket. I don't know if you need one or not. Hey 4onthefloor, I noticed that heater hook up as well. I don't think the circulation will work very well without the pump - maybe it will? I wish I lived closer to that guy. I would buy it for the motor.
