As long as the camshaft lobes clear the baffle, the gap isn't important. Just make sure the cam lobes have enough clearance, and the gap won't be an issue. 1/8" or a bit more will be plenty to allow vapors to enter the road draft system.
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!