35.7 x 29.5mm valves in plasma-nitrided EN214N s/steel with manganese bronze valve guides.Nominal 24-25cc with by pass and heater take off holes open. Supersport head-sold on an exchange basis-old core must be serviceable and no cracks--See
MSE3 for performance figures-perfect for use with 7cc dish on mega pistons 1380cc. Without by pass but with heater hole which can be blanked off.
See
C-AHT135 for a road going version.
Some companies call this a stage 3 head but our way of thinking similar to original Special Tuning is as follows-for 1275 head
Stage1 has 33mm inlet 29mm exhaust std valve sizes and gas flowed
Stage2 has 35.6mm x 29mm ex road quality valves and ported to Road Sport spec
Stage3 has 35.7mm x 29mm ex race quality valves to Super Sport/Grand Tourer spec
Stage4 as stage 3 but with either larger inlet or exhasut valves and more modified throat and port work.
For real race use ask our technical staff at York or Potters Bar.