Any chance its a over sized valve with a worn guide that allows to valve to move over a bit and hit the plug?
I don't think so with that recent rebuild and low run time.
but something unique is different in no.2 and different only at high rpms
ocdart
that took me a couple reads but I'm with ya. get that tab in a different position inside there. I can see a bit of an edge along the wall of the cylinder at the top of the piston at TDC. I'll find that 180* plug and try it out.
daredevil & UOP
I'll do some research to see what I can do. these are "hotter" plugs w/ 3/4" reach. all I need is an eighth and only one.
Car runs fine now (I haven't greased again yet) magnet came out empty, no obvious marks on the piston, until I touched it with the magnet.