Because in reality you can actually have both, if you know what you're doing. The OP's 5-speed overdrive trans is a huge factor in being able to do that.
Optimize WOT mixture for max power, tune cruise mixture to be at least stoich or slightly leaner, run vacuum advance and initial timing + advance curve that gives ample advance at lower RPMs, good ratio spread in transmission for decent leverage on take-off and low-RPM cruising at speed, cam specs that give decent cylinder filling and low reversion at the expected cruise RPMs... and there you go. Several posts in this thread from guys who have actually done it.
@Valveguy just focus for now on getting your tune optimized and go from there. Earlier you said you didn't notice much difference in performance between your current 340 and your old 318 2-bbl from when you were in high school, that indicates your 340 is not running the way it should. 318 is a putt-putt "get mom to the grocery store and back" engine in stock form.