question for knowledge of 1377 valve-all w\knowledge

aftr reading a post bout 2250 #'s mac1 talked about shortening tha valve stem.with alot of more work to get the valve where you want it.

my question is-can you shorten the valve stem on a 1377 or 1322 valve.(same thing)and get more power out of it.i have a ags ft piston and @ 20 pumps i have a small bit of air left..177. and a 2289 w\18 pumps w\charles mellon piston,ftp.same small bit of air left over.

would like to know if shortening the valve stem any amount would increase the power w\out leaving any air in the valve.

valves have had tport mod done.lighter spring in 1377,stock in 2289.ft on both.i've noticed the 2289 has less noise,yet it seems it has more power.hope you can help me answer this question.thank you. jay