actually, i think this rocker will fit best..or atleast the Mancini Al rocker just won't be any better, just different...

quick calc has the PRW roller about 12% towards the intake side, then it should move towards the center as it cycles through the valve lift and perhaps back to where it started.

the Mancini Al arm is .040" longer, say it moves the roller out .030", that sets the roller at 2% to the intake side from the centerline of the valve stem. if the sweep of the roller is say .050" then it will roll ~14% towards the exh side from the centerline.