5 Golden Porting Rules - real detailed porting tech!

In this, PowerTec 10. episode 59, Part 4 of Rule #1 DV explains why certain valve forms work better than others. Why intuition led engine builders astray for maybe as much as the first 60 years of the 4 cycle poppet valve engines existance. Useing computational fluid dynamics (CFD) diagrams the reason that what appears to be the leaast streamlined valve actually flow the best and make more power