HI, I HOPE THIS WILL BE OF SOME HELP IN REBUILDING A 350 TWIN. IN 1968-69 AND EARLY 1970 HONDA USED A 286 CAM AND ROCKERS, THIS ENGINE WOULD TURN 10,500 RPMS AND WAS A REALLY HOT NUMBER. I DON'T KNOW WHY BUT THEY DETUNED THEM IN LATE 1970 WITH A 312 CAM AND ROCKERS. REDLINED AT 9100 RPMS. THE ROCKERS ARE MARKED 312 AND THE CAM IS THINNER THAN THE 286. THE 286 CAM MUST BE USED WITH THE 286 ROCKERS (UNMARKED) AS I RECALL THE SPARK ADVANCE UNIT IS MARKED 286. IF YOU WANT A CLUTCH THAT WILL HANDLE THE HOT 350 ENGINE OUT PUT USE CL/CB77 (305) CORK PLATE, THEY HAVE MORE SURFACE AREA . JETTING, CHECK THE SIZE OF THE HOLE AND IF YOU NEED TO LEAN IT OUT, FILL IT WITH 5MIN, EPOXY AND DRILL IT OUT 0.003 SMALLER. THIS WILL WORK ON BOTH THE SLOW & HIGH SPEED JETS. HONDA JETS ARE IN 0.003 STEPS. COMPRESSION ON A CB/CL/SL350SHOULD BE 171 LBS ON A WARM ENGINE HOLDING THE THROTTLE WIDE OPEN.