You don't need to tap the lifter valley to install a spider and dogbones. That's just one way to do it, but camshaft selection is limited when using small base circled cams. Crane and Comp Cams make link-bar lifters to run a late model hydraulic roller cam in a non-roller ready block. These lifters aren't cheap, though, so it will depend on you how much time and effort you want to put into tapping the lifter valley for the spider retainer. Remember one thing, if you going to make serious power with the motor the blocks tend to split down the middle most of the time and that's where you'd have to tap the retainer holes.


Link to Crane Lifters on Summit Racing