Congrats on a nice jump in performance. It is always a rewarding experience to see your average speed go up like that.

If you don't mind me asking, what is your age? I am only asking because I wonder if you have the aerobic capacity to go even faster. Is 177 near your max output? I think a 150bpm average is pretty good exertion level if 177 is in fact pretty close to your max heart rate.