What is the ignition timing on 1980 corvette L48?

The exact ignition timing on a 1980 Corvette L48 isn't a single number. It's variable and depends on several factors, including engine speed and vacuum. You won't find a single degrees BTDC (Before Top Dead Center) specification that applies universally.

To find the correct timing, you need to consult the owner's manual or a Chevrolet service manual specific to that year and model. These manuals will provide the specifications and the procedure for setting the timing correctly using a timing light. They will likely give you initial base timing and then instructions on how to adjust it based on vacuum.

Without access to those documents, I can't give you a precise number. Attempting to guess could damage your engine.