[LS short box]

Just a note on compression testing and you may know this. All the spark plugs should be out and the carb butter flies should be blocked to the wide open position.
Up here in sunny MN back in the day when carbs were typical many times cars were brought into the shop when it -20 plus out and because the chokes weren't set properly flooded the engine with gas. Standard procedure was to drain the oil to get the gas out of the oil.
Then pull all the plugs, crank it over a bit to clear the gas. Be careful and pull the 12 volt lead off the distributor so you don't get a spark and start a fire from the gas out of the cylinders. Ask me how I know!. Then squirt a bit of oil into each cylinder to get compression back because if you really had a flooded engine the over load of gas washes the rings and you lose compression. Crank it over a bit and then reinstall the plugs and give it a shot. Easy to do and doesn't cost anything except the oil change.