A 4 barrel on an inline six is a solution looking for a problem. You're probably right on the ragged edge of "too much carburetor " for the engine size. I keep going back to the power valve as a possible solution, and you keep ignoring me, so I'll mention it once more and then sit back and watch/listen. Another possibility is a slightly low float level, which is ADJUSTABLE on your Holley. With the engine idling, the gas should be even with the bottom of the hole in both float chambers when the plug is removed. It's adjusted by loosening the screw above the fuel inlet fitting slightly, and turning the adjusting nut- - - -clockwise to lower the level, CCW to raise it. Be prepared for a little leakage- - - -have a handful of rags handy, (and maybe a fire extinguisher). Note the edit- - - -I had the raise/lower direction backwards!
Jerry
