Jerry,
For better clarity, I have a 55 235 in a 46 1/2T. The radiator ia an "exact" copy of the original 46 radiator - close, but no cigar. The fill port comes off the side of the toip tank, towards the engine.
To answer your question, the top of the thermostat is about 9 inches below the opening into the top tank.
I will follow up on your suggestions in the earlier post tomorrow.
Bob
