Valves are not bigger just a waisted stem as are most later heads - flow is still strangled by the throat - you can put all the valve you like, big as you can but without the throat / port being worked nothing gets in that cylindersouthernd wrote:Thanks for the head info, that makes sense. The Vitesse do seem to have bigger valves etc, would they be classed as performance?
Good news is that the work to move the restriction is not very difficult but makes a huge difference.
Going to a big valve and making those work is a bit more involved and where it all starts getting costly. 225 can be had reasonably cheaply - 250+ start getting pricey and 300+ very ££££