Gene Schneider, a Chevy expert that is almost always correct, posted this:

"The coil was mounted with the wire coming out of the bottom up through 1958. From 1959 and up it was mounted with the wire on top.
A slight seepage of oil could be seen on the wire down models but never harmed the coil. Mounting it with the wire on top cured the rather common problem of the wire falling out of the coil and the engine stopping dead."


https://www.chevytalk.org/fusionbb/showtopic.php?tid/276636/