Holley 4492 stock jet size

[VintageMusclecar]

Helps driveability/power a little with the crap gas we have to run these days. Throttle response shouldn't be affected, that's more dependent on the idle/transition circuit calibration and accelerator pump settings (taking ignition timing completely out of the equation just for the sake of conversation).

There isn't really "one thing" that you can do to these old carbs to make noticeable differences, it's more so a culmination of addressing several smaller issues which adds up to a larger improvement (hope that made sense?). These old carbs were pretty damned good out of the box, they just need a few minor tweaks and to be brought back to "as new" condition mechanically.