[niles]

Chifo:

I just went thru same thing with my 393 clev.
I had good water temp reading(80C) but would puck when I stopped, also boiled(sound like tea pot) inside of front of engine.

I found a bad(new) tee radiator cap!. I found the problem after a week of work with the eng builder by blowing into the punk tank overflow tube. I found that I could blow air back into the cooling system. Cap looked perfect, just was'nt sealing and acting as a pressure relief valve. What was happening was with no pressure; at idle or after shut down the water was exceeding the boiling point and flashing a big bubble in the hot head area and the expanding bubble would force water out the overflow

New cap and a good purging of air(very important) no more overflow

gn