not sure but only worth fitting to the 4 valve engines as the 2 valves wont get the full potential due to lack of flow...or so it is said:dunno
i thought they were all 4 valve per cyl pretty sure there was eight in all when i did me valves , there is a size difference with valve diameter dependin on year ,i know chessy has a list of engine nos so he could prob tell ya ,
i`ve got 57`s on mine and its pretty good :biggrin
i`ve got 57`s on mine and its pretty good :biggrin
sorry i meant single plug heads benefit more not the earlier twin plug heads
