In need of the connector piece that connects the rear of the trunk lock tailpiece to the latch directly below it so when the key it turned it pulls up and releases the lock. Hard to describe it exactly as mine was missing when I got the car.
I think this is the piece you're referring to.
I don't have one, just trying to help make it clear.
Looks like one might be able to fabricate that themselves if they had the right metal.
IF I remember right, mine went missing too. I found it between the trunk lid frame and the outer skin... I managed to fish it out.
I made mine with a piece of wire, the wire that is used for suspended ceiling grid. Home depot has the wire in a 10' piece and is very strong and will not rust.
Mine actually had the cast dogleg thingie on the end of the shaft broken off. I just ran a heavy string up thru the back seat area to pull up on the latch. Worked well for the year I was driving the car before it got pulled apart for restoration. The trunk ended up getting decked and an electric solenoid was added to do the job, but I still have a backup pull cord.
Believe this is what you're looking for it's actually part of the lock mechanism.
PM me if you're still interested
Looks very similar to the rod that my 59 has. A bit thicker than coat hanger wire, but much stiffer. Where are you located? If they are the same, there are 2 58 sedans at my local wrecking yard, I hope to go there next week, weather permitting, but I am in Nova Scotia Canada, but I can check to see if that rod is there, and if it looks the same as that diagram, if you like.
Thank you all for responding. I was lucky enough to find one locally here from a 57 Custom enthusiast. Much appreciated!!