A bit OT because it's not a 55-57, but this can happen to any car.
My "other" car is a 67 Nova SS that I updated a bit in the late 90s. Nice original rust free sheet metal, repainted it back then, and put a mild 350 backed by a 200-4R. It's starting to need another freshen up, needs paint (90s paint was lacquer and has aged) and interior, but it's not all that bad. I haven't driven it much over the last 2-3 years.
The last time I tried to drive it, it started and ran but ran badly. Never even got away from the house, it was a big effort just to get it back in the garage. That was a few months ago.
This week I took the carb off and took it apart. It's an Edelbrock 1405. Needle and seats were stuck closed, no fuel in the bowls at all. The floats had big black deposits on them and the bottom of the float bowls did too. Everything else was coated with an awful varnish.
I've never seen anything like this. What a mess!
Looks like it will clean up though. It's probably a better carb to have this happen to than a Holley because of the way it's made - easier to clean than Holley metering plates. I hope the rest of the fuel system is OK.
Advice to self and anyone else. Start and run these things often if they are in "storage". I guess a fuel additive like Stabil is a good idea too.
Too bad I can't buy fuel that doesn't have ethanol in it anywhere near local. Using the premixed non-ethanol fuel in my 2 stroke stuff has really helped there.