Folks,
I just received a reply to my letter explaining at least in part the technical reason for the direction they are taking. Currently it's nearly impossible to verify the plunge cut due to the varying contours. As has been stated here, no tool exists that can specifically inspect the area. I think Imay be able to produce something to reasonable inspect the plug cut which could be used during a tear down. I asked SCCA/NASA to consider this option as a possible solution.
As a group we can collectively petition to work on solving the verification challenge rather than just eliminating the plunge cut. If it were to work we may be able to save our heads.
this is what makes sense to me,
I was going to write this out in the rules proposal before, but kept my mouth shut, Hind sight is 20/20, not that it would matter.
so if we had a cutting tool, that was set, could not be modified, and was available from Mazdaspeed or Enterprises.
The tool would have a center axial alignment to the valve guide, a set outside diameter, and a set end of tool profile(this could be round or square, whatever, just all the same)
Then we could make a simple go/no go gauge that would be simple for tech. what is hard is teching this down in the port. what if we use either a profile gauge type device, that had a center pin to axially align this to the guide.
or maybe a formable foam that can be formed in the port, and a profile go/no go gauge to compare it to.
then the rule would stay almost the same, clarifying that material is taken away from the inside only for the allowed cut with the use of this too, and no blending or reshaping allowed.
this way what is allowed is clear, how to tech it is clear, the rule holding it is clear, and all heads that currently run a plunge would just need a touch with the allowed tool, to clean the end of the plunge to match the profile. yes, we have to pull heads, yes they need to be slightly machined, but this eliminates "hunting" for castings, and allows almost all heads currently used to be reworked. The heads that have been taken too far with port blending would still likely be out.
my $.02