OK, I think Porterfield put me on as a field tester......
The rear pads that came with my car didn't have the "Pantera pin" but I sent them back and they sent me a new set along with a new set of front pads!
Upon checking my front pads for fitment.....I discovered they sent me "unfinished" pads....the hole was not drilled for the locating pin! Sent them back and they promptly sent me a finished set.
Was assembling the one rear caliper that I could at the moment....and ran into the issue that was mentioned above, where "pin" must be filed.... To me, that is dangerous to ship pads that are "unfinished" like that!!! I got no paperwork saying that filing would be needed....and only noticed that it was mentioned above, right now!
The groove in the piston is about .075" deep. The pin is about .090" tall. That is a lot of wrong.....for the money IMHO.
If an unexperienced owner were to assemble the pads without shortening this pin, the potential for lots of bad is great..... wearing rotors unevenly.....gouging up the piston....pads walking in the calipers could wear them in a bad way.....
So, I advised the nice person that was helping me (Wendy) that this needs to be brought to the attention of their engineering group for changes.
I attempted to file the pin, but my files just walked over the top of the steel....perhaps they took on some hardness during the welding process...... So I used my air cutoff wheel and carefully ground them down to fit.
This could be a PITA for a customer....and why would Porterfield want to piss people off.....I'd want to sell more pads!
So, still searching for a good small front piston.......I know they are out there! Found some new ones too, but would be coming from UK, and there are still some unknowns....like dimensions!