Originally Posted by dwydendorf (Post 666760)

The tech guys could sonic check for hollow stems, they allready have a sonic checker for cage thickness.

Originally Posted by Bill Ringer (Post 666761)

There are devices that can conclusively ID the material without removing the head, just remove the valve spring. With the spring off one can check the stem with an XRF metal analyzer. These are accurate and as small as a few pounds. The cost can be an issue as ones just for this type of test would be around $15K new, less for refurbished plus, they can be rented. If there are other components such as chassis parts that need the material verified it's possible the cost could be justified. I've used these, they're super easy to use and accurate.
This article has all the basic info on this technology - https://blog.metalvp.com/articles/ha...-honest-review

Originally Posted by dwydendorf (Post 666805)

I know they are legal, just mentioned that they could use the sonic checker to determine the mass lost by drilling the stems out.