1957 Main Wire Harness Grommet Thru Firewall

[valhalla 4771]

I'm trying to feed the main wire harness thru the firewall. I'm staring at the grommet. It's a puzzle that has me gnawing my fingers. I think I can force the starter relay connection through the grommet. I see no way to get the horn relay plug through, short of splitting the rubber grommet in half and then gluing it back together which seems inelegant. But maybe that's why the grommet housing is hinged to open wide? What am I missing?

 

[sre]

Take it back off the firewall slice it thru from the edge using one of the small holes then thru the center hole. Install the harness then put the metal back around the rubber and install back on firewall.