[oldskewl]

great posting! I haven't heard that good an explanation to that technical a subject in a long time. The only thing I'd like to add.... is the valvejob/porting should be engine specific. If you want a hi compression 12k rpm screamer, you'll have one type, a nice 20% boosted tourer will have, lets say... "a more conservative job required." Also... besides the 3 or 5 angle valve job, a bit on hand lapping is good to. This matches the valves surface to the valveseats surface.