From:Steve Thielicke
Subject:RE: Super X extra spark plug hole in cylinder heads Date:Wed Jun 26 12:08:41 2013
Response to:4743

The holes on the top are not for spark plugs but for most years are a top motor mount stud, in the stream liner years it is just the front that is a mount and the rear is plugged.
Hope this helps you.

Has anyone ever seen this before and what models had it? Looks like an extra spark plug hole cast into the cylinder heads on a '25 Super X engine that I have. Looks like it was done in the factory, not a home workshop modification.