Ross Richardson wrote:
Two years ago I purchased a Lycoming Factory Overhauled O-360-A1A. The
engine is running fine and there was no problems with the core charge. I
believe mine was $4000.00 and it was quickly returned.

Lyc has started enforcing its core charge policy within the last year or so. If
you have (for example) a cracked case that has been welded, no core credit.