4onthefloor, Why is the 261 different? How do you know if you have a 235 non-bypass thermostat? I have not put my rebuilt 261 back in my truck yet, but I installed a brass water shutoff valve in the heater hose outlet on my water pump, so I could shut off the flow to the heater during the summer. Will this be a problem? Here is a pic of the engine w/ the shut off valve installed:
http://community.webshots.com/photo/109150147/120822879MhXjeY
