oil pump question ?

I would start with a std vol/std spring & see if it maintains enough psi (that's the bottom line (to me). & if not then step up to a stiffer spring then up to a hi vol/std spring then hi vol/stiff spring. This just be might be my Sat night OCD & might be able to skip a step/maybe 2. yes pulling the pan is a pain but too much here unnecessarlly stresses the cam/intergear teeth/block bushing & the accumulated slop will retard your cam. PS I am a firm believer in oiling mods & the RODS need to be fed properly. I drilled a .015" hole in the rear of the DR horizontle galley pipe plug 3/8 NPT (get an alum one from speedway or locally). prime it & you'll see the hair thin stream of oil being directed onto the cam/inter gear. Purrfect!