valve/ piston clearance?

Good point!

The ,450" lift is the resultant lift with 1.6 ratio lifters.

Well, from what you're saying I guess i should be fairly safe.
I'll remember to look at the retainer/guide clearance!
Frankly, I thought that valve/ piston clearance was more of an issue, but then again, assumption is the brother of all F...-ups!

Thank's for your answer! :)