Flat tappet lifter failure

[Doug Hoven]

I'm sure it depends from combination to combination, as well as the "harshness" of the cam profile, but it seems like on .390/.410 small block Chevrolet stuff, once the duration @.050 gets into the 270s, cast cams and regular lifters don't seem to last very long. This mostly being down to the added spring pressure in order to control the more radical lobe. I've had good luck on multiple engines with solid lifters from Clay Smith Cams. I asked over the phone who manufactures them, and I got the response Howards/Johnson.