Rktpwrd- did you do the mods all at once or one at a time? The reason being that if you do more than one thing at a time you have no idea what worked and what didn't. I have never found the need to touch the idle bleeds or any other part of a Q-jet beyond the jets, rods, and idle discharge ports. I find the tiny idle discharge to be the single biggest handicap to tuning an emissions carb. Even a bone stock 1980 Pontiac 301 responded well to that.
Mark (if I may call you that, and it’s Donovan, we’re all friends here), I used Cliff’s entire section on modifying the idle circuit as a guide on mine, starting with measuring what I had to begin with.
In that section, Cliff has several “recipes” as he calls them, for modified engines with different camshafts and characteristics. I simply picked the recipe closest to mine and compared his modification recommendations and sizes to my carb. Some of the components didn’t need modifying like the upper and lower air bleeds, but others like the idle down tubes were so horribly restrictive, that they absolutely had to be opened up.
In fact, I didn’t even have a drill bit small enough to accurately gauge what size the orfice in the tubes were!
If you’re more interested, I can grab the book out of the garage and post up here the components that were modified and the before and after sizes.
(And as a footnote, it now idles like an absolute top and runs like a champ!)
