[DaleO]

I know it is likely one needs to create clearance when changing to higher ratio rockers but I have recently read that this may also be the case when increasing lobe lift.

From the Wallace Racing site: "If a higher lift camshaft (.440+) and/or higher ratio rocker arms are being installed the guide holes on the head should be elongated to keep the pushrod from hitting the top of the guide."

Has anyone encountered clearance issues with just an increase in the lobe?

Background and purpose for my question: I am presently at .481" (calculated using a reported actual 1.55 ratio HS rocker) and am looking to get closer to .500 but I do not want to remove the heads for this operation if there is risk.

[Formulas]

I have run a little over .500 lift with steel 1.6 rockers on stock iron pushrod holes.. you should be good from my experience even iff the HS 1.5 is closer to 1.6

parallel to this is you need to know if you have valve spring retainer clearance from top of valve guide and seals for your lift