It's an intake rocker. I'm not sure about right or left, it depends on which way you look at it. I'm going to guess "left", but that's a 50-50 chance of being wrong. The valve arrangement starts with an exhaust valve at each end, then they go in pairs.

X-I-I-X-X-I-I-X-X-I-I-X Count from either front or rear, the line-up is the same. The valves that are angled are exhaust, and the ones that are almost straight up and down are intake.
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!