Check the ignition module in the distributor.
1-8-4-3-6-5-7-2
Its not very powerful at all. I have a 305 in my 1995 Sierra 4x4 probably around 225 hp,
Check throttle positioning sensor.
THere is the Evap canister and associated lines and valves. The engine will not operate properly with this removed.
Per Champion spark plug applications chart, the gap for 1989 Chevy 305 (5.0L) is .035.
The Spark Plug gap is .045
It is important to gap the spark plugs at the right size. The spark plug gap for a 1981 305 Monte Carlo is .045 inches.
if you do not have spark you will not have fuel check coil module and ignition pick up coil.
0.045
.060
.045
5.0L or 305 ci