Sing-grooves, I have tested is and I am amazed...
http://www.somender-singh.com/

My JP Eagle.



It is shown that the combustion is more spread on the piston and did give a better performance. The question is what is legal to modify....

As I told here before the cranktiming can do a lot, but if it is not alowed to modifi the crankshaft and they do inspections you can always alter the cranktiming by modifying the crankcase in the hole under the carburator, they will never inspect that