- Official Post
Here is an Ebay auction for a used C3OZ 6378 A crankshaft washer by Ebay member "bobmannel" with a starting bid of $50.00:
The 289 HiPo crankshaft bolt washer was unique in that it was thicker than the 0.212" standard washer. The 289 HiPo washer part number was C3OZ-6378-A and was 0.325" thick as can be seen on the micrometer. This one is an original.
289 HiPo crankshaft balancer harmonic vibration damper extra thick washer | eBay
-Fred-