Slow 6 more power

I agree with Charlie about the compression increase. The thing is, it isn't something you should guess at. You need measurements to know how much to shave.
But, the first thing you should do is maximize what you have. Good tune-up, adjust the valves, fresh filters, fresh plugs, set the timing...the usual stuff.
Then, use Dan's post as a checklist and tell us what you have. That way, you can get more specific answers instead of general ideas.
$0.02, and done.