Disconnect the battery!
Remove the air intake assembly that is connected to the carburetor or throttle body.
Remove all linkages, hoses, vacuum lines, and wiring from the carburetor or throttle body.
Remove the carburetor or throttle body.
Locate and remove all bolts holding the intake manifold (where the carb was mounted) to the heads and block. Now remove the intake manifold. You may have to pry the manifold up with a flat-head screwdriver to get the gaskets loose.
Next, remove the valve covers and set them aside. Now loosen the rocker arms enough that you can turn them off of the push rods, and remove the push rods.
Now you need to remove the exhaust manifolds or headers and also the spark plug wires.
Locate and remove the head bolts. The type of engine and head will determine how many bolts there are.
Now you should be able to pry the heads loose.