1. What size intake valves are in the heads?
2. Piston to valve clearance has more to do with duration than gross valve lift, so the .542 lift isn't as important as the duration, which as long as your valves are 1.94 or smaller, you shouldn't have a problem with as the X doesn't have a ton of duration.
3. Don't ever take anyone's word for it...ALWAYS do a piston to valve check before you bolt it together and start it without knowing. There are variances in tolerance in every part of an engine and you're mixing manufacturers. You don't wanna be the one guy who got just the right parts to throw together and bend your valves up because they were on one end of the tolerance scale.
I have the trickflow 2.02's with there stage one cam on my stock 88 short block and i could have went with the stage two cause i had enough ptv clearence