Been looking for my Interceptor book for years until today, funny enough was among 1st editions of Y block magazines. if you can read the 3rd paragraph down it shows the firing order of the cam and rotation direction of the marine engines, they are opposite to car as they are viewed from the back. i dug through some old cams and although i could of taken a bit more time and clearer pics you can see the 2nd cam from left has lobes everywhere except 1 & 6 which remain constant. the left cam is older normal regrind with small base circle due to wear, next is the boat cam, 3rd cam is normal cam with "Stellite" hard face lobe tops and one on right is old Potvin eliminater #27. Hope this shares some interest. regards bill.

Doesnt look real clear, the opp rot cam firing order is ;12736845

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia