Dunno if you have seen this but is a great program; http://jimsitton.net/ratiocalc/
Really comes in handy.
I am told this is ill-advised but on my HF, I only removed the externals for the governor. I've never had a problem and it maxes out at 5,000 RPM.
But again, lots of folks think it is not a good idea to leave the gov in. Just wanted to mention the 5K RPM.