Re: Im trying to stay cooler then my car!!
Regarding the radiator cap, a 16 lb cap is a 16 lb cap. Doesn't matter where you bought it, if it tests to hold 16 psi, then it's fine. When you pressure-tested the system, did you pressure-test the cap, too?
A bad head gasket will cause an over-temperature condition, but your pressure test would have shown pressure leakage. On some engines, installing a head gasket backward will block off certain coolant passages, which causes an over-temperature condition.
If the cap wasn't holding pressure, you'd be getting boil-over at a lower temperature, in which case it might not be a true over-temperature situation. But, you said your temperature gauge showed temperature rising, so it would seem the boil-over is occuring due to an actual over-temperature condition.
I'm not exactly sure what you meant by your cooling system running counterclockwise. Do you mean your pump runs counterclockwise? If so, my first question is to ensure the pump is designed to run in that direction (I'm sure you've already verified this).
I agree with you regarding the temperature of the radiator hoses. If you are seeing boil-over, at least one of the hoses should be very hot (an probably both). If you can grab on to the hose for more than a few seconds, then you have some sort of issue preventing flow through the hose. That could be a bad water pump (or reversed), air pocket in a coolant passage someplace, bad thermostat, collapsed hose, clogged radiator, etc.
I guess I really haven't given you any solutions. I'm just trying to think this through with you.