15. Once you have verified the proper pushrod length for your application, you might consider it good insurance to verify piston to valve clearance. Comp Cams recommends checking on its larger Magnum cams and all-out race cams, but for peace of mind, we recommend doing this with any larger-than-stock cam. For hydraulic roller lifters, you need to prevent oil bleed down by replacing them with solid lifters. If you have a spare pair (as we did), you can remove the plunger springs and fill the lifters with a stack of washers to make them “solid lifters.” Be sure to mark them in some way so you don’t accidentally use them in your valvetrain!