Flywheel Timing Marks

Hello,
I have this flywheel off a '64 CJ5 F134 engine. I suspect it's original to the year since the flywheel is drilled for the 9-1/4" clutch. I noticed these timing marks on the side of the flywheel facing the engine. The service manual I have doesn't discuss their use as far as I can find. Can anyone enlighten me?
Thanks,
Ken

 

The militaries and early flatties had a peephole through the bellhousing cover to check timing.

Found this:
“The CJ2A and CJ3A retained the flywheel timing marks and the window. The M38 went to the late bell housing and large frame starter with front pulley timing marks in May 1952. The CJ's made the switch with the CJ3B.”

 

Interesting, thanks. They must have used an older flywheel when they put this engine together.

 

Willys also had a 6 cyl 161 F head (early 1950s) that used the larger clutch and has the timing window on the passenger side of the bellhousing around the 9 o'clock position (passenger side) as you view the engine from the front. I'll bet that is what your flywheel is from. I used to work on a 1950 VJ Jeepster that had the 161 Fhead in it that had your flywheel.
My '64 Tux has the large clutch, but no timing marks like yours.
-Donny