So I just finished up my sons first year of racing in the ISOC. He did really well but his sled was slowing him down in compasison to the other sleds. Besides these mods listed below, what am I missing?
1. #35 space chain, 13 / 54 sprockets and roller chain adjuster.
2. Wheel kit for track.
3. Adjustable main jet.
4. Larger governor spring / zip tye.
5. Tiny Tach showing max RPM @ 6300
6. And finally, cooking oil on track at races........

Is blue printing legal?
Stiffer springs?
3 angle grinding valves?
Porting / polishing?
Milling the head?

Any suggestions you all have would be appreciated.....

valve springs =legal
the rest =not legal
check with rule book, depends on class he is in.
valve springs are good for another 400-500 rpms

Like all race sleds, reducing drive system drag which reduces power robbing friction is key, especially in the minni's.