Ther is no way to get oil to the rocker shafts just bolting that all together. You have pretty much 2 options to do that, for both you tear your block apart, first method: find a good machine shop that can drill the hole through the deck through about 6 inches of iron at a funky angle and make it intersect with a tiny hole in the side of the cam bearin in the block. The second option is to drill and tap a line into the oil galley somewhere and run a transfer tube into a hold drilled and tapped into the end of the rocker shaft.

The best solution is to use the magnum heads the block has already, just bolt on an eddelbrock rpm air-gap intake and carb. They will make quite a bit more power and MPG than your 318 swirl port heads.