1943 M. Over time it got slower and weaker and was getting Antifreeze in the oil. One time, we advanced the timing and it ran ok for awhile but still sounded weak. Eventually it got so slow and weak that it wouldn't stay running. I noticed that it always blew some vapor back out of the carburetor. I assumed it had a burnt or sticky intake valve. I pulled the head and had it totally rebuilt at a good machine shop. The head was trashed from "burning" water for years. It was surfaced, new valves, springs, seats everything. It was magnafluxed and did not have cracks. The machinist said the head gasket was blown. The block surface looked very good. Cylinders and pistons appear to be good. I installed a new head gasket and put the head on. It blows out of the carburetor even worse now. I have good hot spark and good fuel at the carburetor. It blows out of the carburetor so much that the plugs are not getting wet from fuel. I know the carburetor is getting fuel because it blows a nice vapor back out of the carb. Also when I put my hand over the exhaust, I can feel an inward "suck" as well as blowing. If we shoot starting fluid into the carb and hold a hand over the intake on the carb, the motor will pop and hit a few times. I have turned the motor to TDC on all of the cylinders and blown air from the compressor into the spark plug holes and none comes out of the carb (so the valves are seating). When I turn number one cylinder to TDC, both rocked arms are loose and the valves are closed. Could this have jumped timing so bad that it's 180 deg. off? Any other ideas? It's going to be a job pulling the timing cover off to look inside. Sorry for the long story, but I cannot figure this one out!