One of the major differences besides the oil supply tube configuration is the position of the lubrication groove in the rockers. The later model rockers have the groove offset from the holes in the shaft so the shaft retains more pressure and the spit holes in the rockers dribble instead of squirt. Those seemingly minor differences can add up to become major gremlins! I'm working on a couple of possible modifications to the valve train that should make those differences a moot point.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!