in addition to the above to whom it may concern, the production 351 #1 main bearing cam feed hole off the main saddle can be plugged, it is fed off the pressure inlet at the side of the block. the 1/2" main feed to the bearing can also be restricted, i chose to use the same size hole as the rest of the mains. from what i've read a lot of
oil pressure can be lost on the #1 main.
i will open the main bearings at the oiling hole to the same as the
oil feed hole with the correct bit size, and use 3/4 groove bearings, i believe z130m speed pro are preferred.
still undecided on the top end.