Your story totally reads like mine. I had that same observation about not cranking up my HR as much when running compared to cycling. Then I started running much more seriously last fall and especially doing hill reps. I can now consistently bring my HR to 195 and I've even hit 200 once or twice going up a hill at race pace. I thought it was pretty cool (one of my running partners thought it was pretty scary!!!). And it really pays off in hilly races.