The slot for the alignment pin looks correct for an LA.46. The flange at the top of the cylinder looks pretty thick, and if it's a Brian Gardener ABC set for the LA.46, he only sold them with a new head because he didn't want to machine the flange as thin as the stock units are. I think Brian's sets came with a rod also??  Randy Smith made a fairly recent run of VF.46 ABC piston and liners, if I remember correctly. Either way, if you just measure common dimensions of known parts against these you should be able to figure it out. The I do not remember anyone putting out a "recall notice" on any of their P&L sets. If something wasn't machined correctly or completely, you might not be able to assemble them into an engine with out noticing something, so if you have enough parts you could just dry assemble things to see what does or does not fit. More or less a process of elimination. But the short answer is if you have a dial caliper and some known good parts for each engine, you should be able to figure this out in about 10 minutes.
  Good luck,
  Dan McEntee

I think I figured it out. I found an old email from 2017 Randy sent me a piston and liner (has to be the one in the picture) which was missing a cut on the piston. This is supposed to be for the OS 46 VF that I have. Before I send it back though perhaps Randy will verify this.

This is  a pretty strange way your doing this ,  so I will answer this  here, NO that is not  one of mine, I did have a few 40 VF  AAC piston sleeve setups that did not have the cutout in them, and  I did  have  only  1  person that got one, He  told me  NO he  would not  send it back for replacement, He would cut the   piston himself.  The one you have  is  NOT one of mine, as they were  all  AAC... that is  aluminum sleeve setups. Yours  pictured  is  some  ABC  BRASS  setup for something.  If you want me to identify it for you, then I will be  happy to, Send it to me  for  ID
I did not  have  ANY  46  P/S  sets  that  were not  cut

Randy

Well if is not for the VF then could it be for the LA 46 ? At the time I ordered back plate Venturi and NVA for my 46 LA. As well as a Header for the VF.  This was back in 2017. Anyway I will continue this off line as I would really like to figure out what these are for without starting to tear engines apart.

I sold  backplates, Venturis  for the  LA 46  but  not  ABC piston sets, I sold VF headers  and  AAC sets  for   40  and  46,  If you want to know what it is, send it to me and I will  ID the  P/S  If it needs  a trim in the  piston, that is  easy to do I cannot tell  from a  picture, but it does  NOT  look like an  LA  Sleeve

Randy

I just stumbled across this post. It's not something of mine.