Not only is the flex-fan unable to pull a lotta air thru the rad, it also cannot push that hot air down and out. And the more you rev it, the worse it gets, cuz the blades loose their curvature with rpm.
And of course if the carb is sucking that hot and climbing hotter underhood air, the whole thing becomes like a runaway nuclear reactor.
I got stuck one time, in this situation, far from home, when the ambient temp sky-rocketed. What I did was loosen the hood and lifted the back high enough to exhaust some of that hot air, and then I slowed down to find an engine rpm, that allowed that stinking combo to move air. That got me moving to my destination, and allowed me to finish my vacation. But when I got home, that fan came off immediately. and then I set to work, solving this problem, once and for all.
When I finished, I got her to run at 205/207 no matter what, and with a 7psi cap. That was about 2002.
