4 Barrel

OK, then you need to set some pre-load on those hydraulic lifters with the adjustable rockers.

Top Dead Center up on compression stroke. Go to zero lash by tightening the rocker while spinning the push rod with the other hand. When the pushrod gets some drag on it, then go another 3/4 turn for the pre-load. On the 2 valves.

Then it's on to the next cylinder to set those valves and so on. Spark Plugs out.

This should help it to run better just getting the valves set right in itself.