VFT, I think you ought to stick with the original 261 setup. It was designed to eliminate a very common 235 problem of hot spots from steam when warming up.
This is from an article in the tech tips section of inliners international: 'In its pure big truck form the 261 had a larger thermostat housing holding a double acting thermostat: This is designed to circulate water through the block and head before the thermostat opens to allow hot water into the radiator. Thus, no internal steam hot spots during warm ups, expecially in winter. This is particularly important with the very cold coolant. Vital engine spots can become very hot before the total coolant becomes hot enough to open a normal thermostat on the front of the block.' You can tell its a thermo housing from a 261 if it has two holes drilled for the smaller hose fittings in addition to the large one that feeds from the radiator. It is slightly larger than the 235 housing and it contains a hard-to-find by-pass thermostat."
Jerry
