Originally Posted by Uncle Ben
I would put my money on a plugged water passage in the block or a upside down thermostat. F's are natorious for plugged/caked up water jackets usually around the center and rear most cylinders. 2F's started putting steam holes at the head deck to relieve dead coolant movement problem. Heater cores usually flow from bottom to top (heat rises) while radiators flow from top to bottom.
Good idea Kevin. Both F blocks I recently stripped were REALLY blocked at the lower, rear passenger side drain hole of the water jacket. On the block I used for my build, I ended up using a drill to clear out the crud after poking and scraping with a screwdriver was ineffective. After I got a hole going with a drill, I then used the screwdriver and several other various poking-scraping implements to clear the passage. Inside, there was crud, but it will aloow free flow of coolant.
I can see the advantage to having one's block dipped.
For Max's issue, I'm not entirely sure having the lower, rear portion of the block's water jacket filled with crud would necessarily lead to coolant temps being too high. That part of the engine doesn't see nearly as much heat as the head. My guess is that it's an overall heat-shedding problem rather than a hot spot. Similar to so many improperly done V8 conversions.