[TJ's Chevy]

After idling awhile the filter will not be full....that's because the float has shut off the need for more fuel...then you rev the engine up and fuel comes crashing through the filter cause the float opened again and released the pressure. That was common on my engine anyhow. I'd adjust the valves...adjust them to .004 for a start and see how she runs...then to 0 lash with a 1/4 turn of preload. If that don't do it...see what the gap is on the plugs. To much gap will cause rough idle because there's not enough spark advance. With an HEI I set mine at 10 initial, but every engine is different.