[Excaliber]

The point I was trying to make is, just because it's a Windsor doesn't mean it HAS to have a by-pass. It depends on the heads and water pump if the stock style by-pass would even work. Put Cleveland style heads on your Windsor and you won't have a working by-pass. I'm thinking KC had a reason for blocking off the by-pass, which by the way, is NOT required for any engine, it's just nice to have for a street engine. Closing it off will increase over all water flow gpm (increasing cooling capacity).

I don't think it has anything to do with the problem this thread is addressing. I'm thinking the primary problem is: Air in the system or a sticking thermostat which is opening/closing erratically.