35.6mm(1.405") longer inlet valve for the original 8 port head pre 2012 spec only for use with silicon bronze guides these are plasma heat treated to eradicate premature wear from unleaded petrol.
The valves for the current 8 port heads from 2012 were made slightly longer than these where we increased height to bring in 21cc combustion chambers
early valve is 3.870" 98.292mm long