Shaved Flywheel Bolt Heads, Any Ideas Of Why Flywheel Bolts Are Ground Down 1/2 Options

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Does anyone have any ideas of why the flywheel bolts have been ground down as in my attached picture? This motor came out of my 1976 - 914. I am in the process of cleaning up and painting the car. The engine as per the serial # is an early 73 2.0. Ser # GA000605. The heads as per the casting numbers are 2.0 L off a VW bus. I am thinking the motor was put together after the OE 2.0 L gave up. The OE 901 5 speed tansaxle is bolted to the current 73 2.0 L.

The flywheel looks like a 914 flywheel and the clutch plate looks correct but someone who put this engine together shaved the flywheel bolts for a reason. It looks like the bolts were ground down on the bench and then installed and torqued to the crankshaft. The bolt shoulders are 1/2 the OE height but with the right socket I would think they were able to get 85 ft lbs on torque. The clutch plate would have contacted or come very close to contacting the full length flywheel bolts if they had not been ground down 1/2 in height. And if the clutch plate over time wore down to the rivets you would have clutch plate contact with the bolt heads at full length.

My thoughts are the flywheel may have been surfaced down so much they had to grind the bolt heads if the outer bolt up surface point for the pressure plate was not also machined down at the same time. It may also be possible the flywheel is a different depth at the flywheel bolt center point and maybe a VW bus flywheel or they may have a bus clutch plate installed.

It does have a new Sachs clutch plate stamped with P/N 1861540033.

Anyone have a good explanation of why the shortened flywheel bolts?
Thanks.