I would suggest haveing your welder weld up/shorten the slots in the cam plate then file em open to get the amt you want & there's the FBO plate tho people have complained that the too large center hole lets the plate shift changing the amt (no opinion/exp with that) & the hole ID could be reduced. If you have an early 70's (non Mallory based) dist that is what I would do. For a recommendation for a dist here is a BTT for ya.