Anyone with firsthand info on use and spring rates with Schubeck ceramic solid flat tappets. May use them in a 408 with lunati 30200743. I have ported eddys with pac 1903 springs in at 1.80. Thanks
Preface - I don't run them myself. I build street and street/strip engines and I've never needed to. However I have friends who tried them in Stock Eliminator Fords when they were first hitting the market. Schubeck's gone and now I think it's SM Lifters that makes them. They are, as mentioned, very susceptible to chipping on the face if they are allowed to bounce. Lunati wants a slightly lighter spring on that cam than the PACs you have. You could probably gain a little power by using a spring closer to what Lunati recommends but I don't think you're hurting yourself by using the PACs you have.
