Along with everything else we have been doing to the 235/1956 3100 we will need to take the heater core out for a leak fix. We would like to replace the anti-freeze with Evans coolant. The block must be completely drained. I was told that you can remove all the hoses and the thermostat and wrap a rag around an air hose and force air into the block from the thermostat housing to force all the coolant and water out.....??? Since we can't get the block drain plug out and do not want to break it off is this other method an option ? Thanks Steve