Technical Can anyone identify this distributor?

Can anyone identify this distributor? Realize it’s missing the lower shaft?

 

Looks like a one-off, completely machined from the solid. Even the rotor is milled from a block of phenolic. Obviously 8 cyl, but for what?

 

Not sure what it was made for or originally fit. The 393-2796 trigger is a Mercury marine part number. Means nothing if it's a one off, but may be a clue?

 

Thanks jmountainjr. You may be onto something….there were Mercury boat parts at the estate sale as well as Flathead parts.