1975 corvette cuts out then dies once it gets warm

Have you looked at the carburetor? The float may be bad and not letting enough fuel into the carb bowl to feed the engine. Do you have cats that may plug up and prevent the flow of exhaust gas so the sensors shuts down the engine? If you have spark at the plugs when the engine stops, there must be a fuel delivery problem. When did you last change all the fuel filters and are they in correctly? Is there any particles in the gas tank that slows the flow of gas to the fuel pump or through the lines? This is a car with advanced age, so there even may be a cracked fuel line or lose hose. Do you smell gas when you shut it off or when it quits? Start with the spark, easier to check. If you have a friend with a good carburetor, try swapping it out and see if that will fix the problem. When it stops, remove the air breather and see if fuel enters the boars from the jets when the gas peddle is pressed down. How long has it been since this 39 year old car has had the heads reworked? It may even be valves failing to work correctly. Broken spring? Bad cam shaft of cam bearings? Timing set properly? Does the 1975 have computer modules? Old modules develop cracks and when warm, expand and break connections. You have a lot of fun work cut out for you.

Carb adjustment needed. Check timing also.