It sounds like you have exhaust leaking. Checking your project photos, it looks like your head had AIR, I would pull the plugs and check that they have a copper 'o' ring or other means to seal them from the exhaust pressure. Someone may have just put bolts in the ports.
On the water leak, I think you are right about the stock gasket, make a new one and maybe use some hi-temp RTV.
Tim
Correct. It is a 1973 engine. I used the stock plug to seal the AIR holes. I sliced each one off the air distibution tubing and removed the stub that was left. I then tapped the hole that remained in the center of each fitting to accept a 1/4-20 set screw which I installed with JB weld. I also excluded the tube that sticks down into the exhaust port. I screwed this assembly into each A.I.R. port. I'm thinking that one of those two items I removed is what created the seal you speak of. Good observation. I will do some measuring and fabricate 6 copper O rings and see if that makes a difference.
I have some gasket material from another project that worked well sealing cooling system coolant and pressure. I will fabricate a new gasket from that and replace the stock metal based one on the heat plate.
Lurching towards success one step at a time.
