1975 Other Chevrolet Models

Do below and comeback with some results

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, distributor pick-up coil, ignition control module, cam and crank sensors- Note: If it doesn't apply disregard it

Ground it to any good ground point about 1/8 in away from the ground. Use the valve cover.

It won't spin over by using the starter? Put a socket with a breaker bar on the crankshaft bolt and try to turn the engine manually, if it still won't move, remove all the sparkplugs, and try to spin the motor with the breakerbar again, sounds like the headgasket blew and you have a cylinder filled with coolant. Let me know how you make out. Lou

The engine was running really hot and eventually it died

If the word was overheated I would have given you how to check for hydrolock, lout5369 has given you a good advice follow it and get back