I've spent the last couple days reading thought all this, as I didn't know about the vent issues before I didn't install Wayne's cotinuous vent.

I did have success elevating the radiator. Is usually uses ratchet straps and hooks in my celing to hoist the radiator up and keep it level. Doing this makes the radiator cap the highest point in the system again. Next I removed the air intake to get access to the radiator return line. I loosened the hose clamp and pinched the side of the hose by the end to let the air out, keep filling from the radiator it works great now. Temp gets up to about 190 idling then drops back to 178 and the highest temp I saw while hard driving was 207. Way better than the 248 I saw while idling before.