Thanks all for your help. I will most likely use ideas from each of you. The heater that is in there is very fresh and the hook ups on the inside fire wall should come off easily. They are new ones; I think without the little collar. The weather is warming up some, and I might go out today. What I am going try is taking the hoses lose in the cab and putting one end in a bucket and try the air pressure idea. Hopefully, the firewall hook ups are higher than the block and radiator top. Clearly, I could drain some coolant. If I do unhook the hose from under the hood, I will loop the hoses together from the tap to the heater tube. IMO this will help the coolant flow through the head. I have another heater I can put in. It is a Moss matrix heater that I added some filler. I basically cut some plywood in a circle the size of the core to shim up the gap so the matrix heater does not sit so high under the dash. I used the old bigger clips and painted the plywood black so it is hard to see. Perhaps I can post a picture if I can come up with camera.
Steve