Photo of the top (part of) of one of my pistons (or at least I thiknk I've uploaded it...). It's like that all round. I took a nice video but takes too long to upload.
Basically there are no valve clearance recesses so it would appear my August 1999 Chimaera 400 is not a high lift cam.
Good detective work Latham91. That puts a big old dent in the "all late 400s are High Lift Cams" theory. Enough to conclude its a "busted" myth? Probably.