Hi!
Raising the exhaust is one thing you can do...But! Problem is that when using a Dremel with a diamond cutter might crack the nickel plating.
Reducing friktion is a good thing to do. Changing to Swiss made WIB C 4, racing bearings is making the crankshaft turn easier (These bearings are used in JETT and Nelson pylon racing engines).
It's also a good idea to lighten the piston and conneting rod (all things that reciproce).