Mopar P-9-6S Spark Plugs

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Anyone know what the above plugs fit?  Searched on-line and can't find any information.  Thanks.

[HP2]

Looking at the threads and plug reach, I'd guess it to be a big block plug with a small hex size and shorter insulator body.

Some pictures here:
https://www.ebay.com/itm/114763412288

[blown motor]

Looking at the threads and plug reach, I'd guess it to be a big block plug with a small hex size and shorter insulator body.

Some pictures here:
https://www.ebay.com/itm/114763412288

I messaged the seller but they didn't know what the application was.

[Strawdawg]

From the comments that come up in search, I would guess pre WWII

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Thanks all.  Insulator body is short but a larger diameter than typical plugs.  Was figuring old and pre-WWII makes sense.  I bought a couple off of ebay for the boxes for display purposes and was curious what the application was.