69 383 Water Pump Housing Casting Defect?

440 Mike said
That stop leak is some nasty stuff. I spent hours flushing out a 440 bare block on an engine stand with all of the core plugs removed. Had to use hooked wires and roll the block at different angles to dig all of the debris out. It will be tough to get this block clean while still in the car. I'm sure that there are pockets/passages in the block that are plugged solid.

Well I hope that it isn’t too bad. Was hoping to not do a block tear down since it has already been 3 years getting this car road worthy. I still don’t understand why the temperature drops 20 degrees in around 10 seconds when turning the engine off and on again. Its a mechanical gauge, so no reason why it should do that unless the thermometer is reading a drop