Starting it up after sitting for 5 years

I would change the oil and filter and fill the filter up, pull the plugs and squirt a little oil in the cylinders, attach a gas can with a rubber hose to the fuel pump(no telling what's in the gas tank), and install a good battery.

1: remove the plugs and run some good penetrating oil down the cylinders and let it sit for 24 hours. then turn the engine over by hand at least one revolution. if it turns over, then go to step 2. if not repeat this step. if it still doesnt turn over, then you may have an internal problem.

2: change the plugs, plug wires, etc. add a new battery.

3: change the oil and filter. fill the filter with oil before you install it.

4: rebuild the carb.

5: using a drill turn the oil pump shaft until you get oil pressure. you may have to have the ignition on.

6: replace the belts and hoses

7: replace the old coolant with fresh. this would be a good time to flush the cooling system. replace the thermostat.

8: reinstall the distributor.

9: prime the carb with fresh fuel. i would also drain the tank and add fresh fuel there as well. you may also have to replace the fuel pump. they are cheap, so i would go ahead and do it.

10: with the transmission in neutral, and the coil disconnected, crank the engine over until you get oil pressure. then reconnect the coil, and start the engine. run it at 1500rpm for about 15min before letting it idle. this will run plenty of oil around the engine, and prevent things like wiping a lobe on the cam. while then engine is running, check for leaks.

11: change the oil and filter, then change it again at 1000 miles and again at your normal change interval.

at this point you can now adjust the idle, valves, etc. checl for vacuum leaks.

replacing the clutch in a C3 vette, like you have, is a major hassle. the problem is that there is little room to work around the bolts that hold things in place. otherwise it is like changing the clutch in a mustang.