how hot is too hot

I have a 360 bored .030 .474 cam with 10.7 compression and been having cooling problems. My fuel line or something fuel related has been so hot that it vapor locks and the idle goes up because the carb starts running lean. I switched to a 160* from a 180* thermostat and it made things worse. I have a 2 core stock radiator now but I've got Griffin building me a new radiator. I would get out on the hwy and it would get in the 210* range and start wanting to shut off and act funny (vapor locking). I've got a shroud coming also and going to try all different type things. Even a electric fan in front of the radiator used as a pusher. Until I get everything installed I won't know anything but I know what I have isn't working. So I find this thread interesting to say the least.