..owners may find the link below of use.
It confirms what I have been saying for many years that dryflow tests are worthless, wetflo is the only true way to go, velocity is more important than cfm,normal 3 angle valve seat jobs are now out of date!

Wow..I guess they just caught on!!!

Worth a read...

www.enginebuildermag.com/Article/16025/the_inside_angle_on_valve_seats_what_you_need_to_know_to_go_with_the_flow.aspx

Excellent article especially about the small details on the machining processes. Its sometimes hard to believe how 0.0002" can make so much of a difference. I also like the quote
"engines run on velocity,not cfm flow numbers" I'm wondering if "other" backyard engineers use this principle?.......go figure

This post has been edited by Speedmaster: Aug 28 2008, 04:34 PM

good article. You know, I'm surprised no one has developed a CNC valve seat cutter that makes a smooth radius seat instead of multiple angles.

That is very good information, but now the question is what are the correct valve seat angles for the 2.5 and 3.0? Also were to find a shop that meets all the requirements for doing it right.

....a few gash old heads and a few $$$$$ would set you up with testing etc on a wetflo rig with multiple types of valve job to establish the best.But note that a lot depends on valve size,cam lift etc etc...My point, and has been for many years(around 30!!!!) is that velocity is the part of induction that makes the power re cylinder filling at higher rpm. The other message from this is that most m/c shops still use old tech and so many owners think that that because a head has been m/c and 'looks cool' that it will improve performance..as you can read this is not so.Save your dosh ($$$) until you know from wetlo that the head can be improved etc...don't just have it m/c because you 'think' it's better / 'looks cool' to see shiny cut metal!!

Radius cutters have been around a while. They're not always best for every application.