It is very rare for a leak in a small block--the crank seal area is nicked I bet--Not much else can cause a leak on a small block.
A big block..holy %$#@!! I went 24 years / never had one leak. FelPro started making seals offshore and Kaboom!!! I have used every trick in the book, invented a few new ones , and to this day I HATE doing a BB for that reason.
A small block can be fixed even if you use a China seal--If it was a big block....I would sell it.