13a. With a Proform spring micrometer, Brent set up the stock oval port heads. Brent said, “I run a lot of spring pressure with hydraulic rollers and link bar lifters. I didn’t use Crane’s specs, but set the install height to give a 170-pound seat and a 425-pound open pressure. The Crane lifters are very high quality in terms of body design and material, so they will withstand the pressure.