I've looked through the posts here, but may not see an answer to my question.
My understanding was the bypass thermostat was required on the 261 to help prevent parts of the engine heating unequally since the cylinders are siamesed.
The 261 I had had the larger thermostat which had a small circular metal piece that would seal against an opening in the lower part of the the thermostat. This engine was out of a 1960 Chevy school bus that had a Viking 60 Chevy frame and drive train.
I guess my question is, did the smaller trucks (pickups and such) not need the bypass feature on the 261?
