For what it’s worth: as many folks have suggested, I briefly considered routing a secondary wire (like a metal clothes hanger) through the firewall as a backup in case this ever happens to me. I even went so far as to do it, running a metal hanger through the firewall (there happens to be a hole on the firewall of my ‘57 right above where the original cable goes through) and connecting it to the hood release mechanism. Took 5 minutes. But I ultimately uninstalled it after making sparks fly while routing it through the firewall by accidentally touching one end of the hanger to the starter relay. The idea of having an ungrounded bare metal wire running through there all the time just makes me too nervous. (Just speaking for myself: I know a lot of people have done it and are comfortable with it.). I ultimately decided to just buy the hood release tool from CASCO:
https://www.classictbird.com/mobile/Tool-Emergency-Hood-Release/productinfo/TL9/. I’m sure that using actually using that tool would entail a lot of grunting, contorting, and swearing on my
part; but it’s cheap, and having it gives me peace of mind without having the (perhaps irrational) worry about having a bare metal wire next to all of those live electrical contact points. (If the jury-rigged wire ever came loose from hood release mechanism, the end in the engine compartment would potentially be flopping around near the starter relay, the battery terminal, and the wires in that area. And I’m not skilled enough to be 100% sure that I could rig in in such a way as to be sure that that would never happen.)