Thread: Should my valvetrain be ok for an S1X cam?

Originally Posted by darkhorizon

1.9 rollers are a very small upgrade in peak lift over stock on a XP or s1x. 1.8s are considered a nearly insignificant upgrade over stock rockers in lift.

You probably do not need clearanced guides with 1.9 rollers on a xp or S1x any more than you need it with stock rockers.

I just can't see how 1.9 rrs would work with an s1x or xp, especially if we are referring to stock heads. Maybe with stg3 ported heads and 130# springs I can see running 1.8s, but seriously 1.9s??