91 chevy scottsdale 4.3

Make sure battery has a full charge? If it cranks good but won't start, have a helper crank it while you check for spark at the plugs. If spark everywhere, check for proper fuel pressure and fuel injector pulse. As far as spark, did you check primary voltage to ignition coil, pink wire, goes hot with key on. Use a test light to check for voltage. Some distributor caps have a tach terminal, you can use a test light there, engine cranking, see if light will pulse. If ignition coil separate from cap, use test light on negative side of coil, if possible, the light should pulse with engine cranking.