What you have to remember is that the lifters and the
oil that goes to them has nothing to do with the top end. The FE engine
oil the top end with holes from the number 2 and 4 mains with a
oil galley up the block to the deck where it passes to a oil galley in the head and up the rocker bolt through the rocker shaft. You restrict the oil to the top side normaly in the head where it comes up to the rocker bolt or at the deck of the block with a .060 to .090 restrictor. It is pretty common to also restrict the oil to the lifter oil galley as well when running a sold because it does not need the extra pressure and capacity to pump up the lifter like a hydraulic does. The style of solid lifter being ran and the condition of the block will determine how much oil is lost around the lifters. We will normaly restrict to .060 when running the solid lifters and you will be amazed at how much oil will go through that small a hole. You would rather the extra oil go to the bottom end for lubrication and cooling of the crankshaft and bearings. This is more important on a wet sump system than a dry sump system because of the capacity of oil and the dry sump cools the oil better. You want just enough oil for lubrication but you do not want a lot of blead of at the lifters and up stairs. Remember the early blocks were not drilled at all for the solid lifters and lubricated the lifters and camshaft from the splash from the crank and rods. I like about 30 at an idle and 80 PSI at wide open. To much oil pressure cost HP and builds heat in the oil. Good luck, Keith