Quoted that directly off of LCE's site. It says "WARNING: LCE highly recommends using our Pro Camshaft Kit Part# 1020000 in order to allow proper spring retainer to guide clearance for any cam that has over .450" lift or in any application that requires a sustained RPM of 6,000 or higher" and that cam has .460 of lift. It also says on their site to hone valve guides to proper clearance.
I have been all over LCE's site many times. I've been down to Lake Havasu City toured their shop and talked to the guys. I read the same thing when I was looking for the cam specs.
At least two things are possible... 1 - that cam profile 14 years ago was different, an 2 - LCE discovered through mechanical failures or other information, that they needed to add the kit and mods to use this cam profile.
Gnarls.
