Chip, I have noticed the plugs in my vehicles won't color properly anymore, something about the gas.Check new vehicles, black pipe, pull a plug ,pretty white in color.I jet the primaries by leaning down until the engine stumbles slightly when accelerating easy at perhaps 40 mph in high gear when the engine is fully warmed up. Then go up one jet size.This also depends on the accelerator pump being adjusted properly.Secondaries are more difficult to jet, but again Holley carbs are usually jetted close right out of the box.Your bogging does seem like secondary the opening rate is too quick.Holly claims if you have to rejet 8-10 sizes from the standard jet size, you have the wrong carb or fuel delivery problems.Holley has a nice catalog/tuning book you can get from their website
