[Tom Vaught]

Don't blame the carb for a lack of tuning knowledge as far as Holley Carbs go, vs a Q-Jet, HIS.

At high speeds/rpm conditions, the carb will want to go rich or lean depending on the calibration and high speed air bleed configuration. You want the carb to "flat line" (maintain the same air/fuel ratio) at high rpm.

The only way to know that is by logging air/fuel ratio on the track at high speed and load.

Power Valves/ Power Valve Channel Restrictions are used on street carbs at high speed to hit that flat line condition along with high speed air bleeds. The trick is to know what the curve or flat line needws to look like before tuning.

Many just do the trial and error set-up or pay a carb guy to get it close and leave it alone. In both cases you waste money on gas trying to get it right. Listen to the air/fuel gage and the engine, as well as the track segment numbers:
60 ft, 330, 660, and 1320 times and top mph number.

All I can do for you guy. Your carb/ your engine/ your program, take ownership of it vs help me, help me, where you just write the check.

Tom V.

ps At High Speed/ High RPM you want the HORIZONTAL LINE shown on the right side of the picture/graph. The picture shows a curve which happens often.
You don't want too lean but you also do not want too rich at high speed 12.7 - 12.8 A/F is a good number to shoot for. The "Lean to be Mean" guys kill a lot of parts and this is for the average guy.