I'm in the process of freshening up a low mileage 318 and getting close to cam selection. I know what will work as far as cam specs go, but this engine is a 1989, first year for hydraulic roller lifters. I came across a 1997 article by E.F.Nowak about Magnum head conversions and in the text he states that you need to run the type of lifter the block came with. He says the lifter bores are in different locations in the blocks valley when comparing roller and non-roller engines. I didn't really want to run those heavy hyd. rollers. Do I have options?