Modified 3.2L crank from a 3.6L racing engine. We think this was caused by ignition issues from a failed factory 3.6L distributor. Not from belt failure, but by bearing failure.
The distributor in question was bought used and had a new belt and a mag pickup installed about 5 hours ago. No sign of bearing issues at that time.
Not sure when the issues started, but the end result was a broken crank at Sears Point about a month ago. No fun.
I have since purchased a JB Racing distributor. Impressive part and company.
Keep an eye on those 964/993 distributors-- they are getting older and older. Not just the belts.