Having lived with carbureted cars for half my life, and EFI cars for the rest, I can't believe anyone would toss an EFI system to go back to carburetors. Instead of changing all that stuff on the engine, why not mod the fuel tank and fuel system (pump etc) and retain the vastly improved driveability and economy of the EFI system? The wiring isn't that complex for EFI, most of it is taken care of at the end of the harness.

As far as looks, a 5.0/302 of any kind in a '55 isn't going to look "period correct" no matter what. It may be easier to get parts for than the correct Y-block, but no one is going to mistake it for an original engine.

Add up the costs, I think you'll find the EFI is cheaper and better than going carb'd.