You even did a few tricks that Team Green didn't...
Oh goodie... that's a start
Want more power?
You need to up the compression and change the port timing...
More power on top requires more cylinder lift but you will loose some bottom end
This chart is to give you a rough idea of what your in for.
The reason I say a rough idea is because every KX500 is a snowflake... They are all a little different.
Get a degree wheel to get it right..
Sometime in the last year or so Cometic added several new thicknesses of aluminum available for spacers.
Available Thicknesses: .010, .016, .020, .025, .032, .040, .047, .050, .063, .080, .100, .125, .160, .188, .217, .250, .313, .375, .500, .625
No need to check all of these but here is what sort of lift numbers you can expect from these stacks of gaskets and spacers.
.020 base gasket = 187 degrees of exhaust port timing
(2) .020 base gaskets + .020" aluminum spacer = 190 degrees of exhaust port timing
(2) .020 base gaskets + .025" aluminum spacer = 190.5 degrees of exhaust port timing
(2) .020 base gaskets + .032" aluminum spacer = 191 degrees of exhaust port timing * SPECIAL * I really like 191 for the best all around performance.
(2) .020 base gaskets + .040" aluminum spacer = 191.5 degrees of exhaust port timing
(2) .020 base gaskets + .063" aluminum spacer = 193.5 degrees of exhaust port timing 14.27:1 for peak hp and torque
(2) .020 base gaskets + .080" aluminum spacer = 194.5 degrees of exhaust port timing
(2) .020 base gaskets + .100" aluminum spacer = 196 degrees of exhaust port timing
(2) .020 base gaskets + .125" aluminum spacer = 197 degrees of exhaust port timing
(3) .020 base gaskets + .040" aluminum spacer + .080" aluminum spacer = 198 degrees of exhaust port timing
Another issue you will run into is the higher the cylinder sits, the more you need to shave the top down to keep your correct squish.
Then, you also have to change the combustion chamber to to get your compression back because you have less trapt volume
