172 Driver.
It's been a while, so I may be a bit hazy, but temperature has a big effect on charge density, so that even with constant MP, as you climb the reduction in OAT means the charge density is higher. Sort of natural intercooler!
411A, remember sitting listening to the drone of big recips, and observing the F/E constantly trolling thru the oscilloscope, and the dreaded "oh !!!!!" followed by "double secondary short" or some other catastrophy.
Have to admit I am glad those days have gone. Along with runaway props, and janitrol heaters cycling away next to thousands of gallons of 115/145.