Safe max lift on X heads that retainer hits seal @ .550??

I use the metal clad blue viton seals. They seem to last pretty good. The stock type black one do end up getting hard, then they break up and end up in the oil pickup screen.

Your end lift result depends on the rocker, shaft position(if its been shimmed or not), how far from shaft center line the adjuster is where it meets the pushrod, how long the pushrod is and the angle of the pushrod. You can get it as perfect as you can, but you will still lose lift on a 59* block no matter what. Most of the time, to get the real theoretical lift, you have to use a 1.6 rocker.