Get maximum rpm from your lifters.
These mechanical lifters from Crane should be used when hydraulic cams have reached their maximum rpm potential. Mechanical lifters are noisier than hydraulic, but have an rpm potential of 8,000 to 8,500 rpm. The engine must have an adjustable valvetrain system, and the lifters cannot be used on a hydraulic camshaft.

Lifters, Mechanical Flat Tappet, Buick/Cadillac/Chevy/Oldsmobile/Pontiac/Rover, Set of 16