Here's some videos on porting. Examples for what you need to clean up for better flow. The faster, smoother the bad air moves out, (exhaust) the quicker the transfer ports move the good air moves in. (Mixture) View: https://m.youtube.com/watch?v=V8oCOIHI_G4 View: https://m.youtube.com/watch?v=rXzRwi2C2xM
There's more videos on porting. You can raise the exhaust port and change the port timing. But remember we're moving the power more at the mid to top end. When moving the exhaust port up I advanced the timing a tad also.
