Bolt Pattern Help Please

I have a 1963 F-134 motor, rear motor plate, and bell housing that will be used in my 2A.
QUESTION: what are the six 5/16 bolt holes for? Neither the plate nor bell housing has the bolt holes for them.

Was this some sort of military thing which requires special parts?

SEE PIC

 

I believe it was for the water proof bell housing.
Jay

 

OK, but what did it LOOK like? I have not been able to find it. Have found M38 & M38A1 bellhousings but neither have the inner 6 bolts. The rear motor plate would have the extra 6 bolt pattern too? You have a lot of military stuff, do you have anything you could take pics of ??? Sorry, I'm very curious and wonder if there is any advantage to the strength of the bellhousing/clutch assembly.

 

Jim
Here is a eBay add for a M38a1 rear engine plate. It looks to have the bolt holes for them.
Jay

Engine Backing Plate Fits Willys M38A1 M38 jeep (TU22) | eBay

 

So it's the backing plate that's different or part of being so. Bet the starter and bellhousing is odd ball to. Might give them a call just to understand this odd set up.

THANKS JAY!!!!!

 

I think it was part of a waterproof clutch system the military had at one time. Jay might be able to add input on this. I'm not sure the waterproof system worked out for the military.