Just finished this 'light' build. Same bike in both graphs. Bike configuration is; stock exhaust, K&N filter, open lid, with a PCV. The blue curves are the stock engine, with before mentioned external mods, tuned. The green curves are with thin gaskets installed, head porting, valve touch up, mechanical timing chain tensioner, NGK spark plug, and a re-tune with PCV (yes,still stock exhaust). The head was not ''milled''. Both graphs are on same 93 octane pump gas. The gains are strictly from said build mods, no foolery, only head and cylinder were off. Very happy with results using mostly stock parts. Bang for buck this makes a GREAT street engine. I think member dobr will be very pleased with the power plant. Thanks for letting me share the data with other members. I will be offering a head service in future post regarding the "engine kit" parts and prices. Let me know your thoughts on this build and or questions. On a semi budget oriented build I don't think you can beat this combo. With a proper aftermarket exhaust system (Akra/Arrow/Yosh) I would suspect to see some more gains too. How much? Maybe an added hp peak and some more front side... This has added 4 hp/10% peak from box stock! PCV, K&N filter, lid mod, set of thin gaskets, mech tensioner, NGK plug, and head work = killer set up at a very affordable price. Roughly the same price as a full exhaust system