Check to see if the valve lift is causing the spring retainers to hit the stem seals. On a high lift cam, it's usually necessary to shorten the top of the guides a little to avoid retainer to seal contact. You'll need about 1/16" (.060) clearance at max valve lift.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!