I made my own external harness for a 1959 Fastwin using soft copper tubing for the connectors. Used the internal/male connector as a jig to glue up the cables/connectors with liquid epoxy, then encased it with black pool repair epoxy putty.
https://goo.gl/photos/sn7pNWyUxjHJebZQ7
http://www.omc-boats.org
http://www.aerocraft-boats.org
