I'm attaching a link to a thread that includes instructions about how to convert a 235 thermostat housing to one with a bypass. Relatively easy project to do. Works great based on how I have been testing it this summer in the Arizona desert. No spikes, fast engine warming, more consistent temps and lower temp readings than before.
https://www.stovebolt.com/ubbthread...ing_a_216/235_thermosta.html#Post1163318This version will only work on a late model 235 or 261 with a low water pump, not a 216/early 235 with a high water pump or a late 235/261 converted to a high water pump. The high water pump does not leave enough clearance between the new bypass port added through the base of the thermostat housing and the water pump.
As stated in the link, Hotrod Lincoln and I were working on a version for the high water pump engines. We have a solution figured out that uses a stock thermostat, but neither of us has built a prototype to test yet. If anyone is interested in moving forward with the project, I can share where we left it and someone can take it from there. I have a few extra thermostat housings that I collected for the project that I'd be happy to send to someone who wants to move the project forward.
Matt
