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7029241 Buick carb

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srb12:
Can someone give me the specifications for the carburetor of a 1969 Buick 430 engine with automatic transmission? Everything stock, except the air cleaner. 7029241.

Unfortunately I'm the owner of a commercially remanufactured unit which is no good right now. So I'm trying to get it right.

Shiny:
Not sure what you are looking for but Cliff has a link to adjustment specs and there are old Delco part number summaries online.  If these will help and you need links, just ask.

srb12:
Sorry for the late reply, I have a lot of trouble accessing this forum. Apparently my IP is banned and I have to access using my work's VPN.

I also reached out to quadrajetpower.com and according to them these would be the specs:

Idle tubes: .032
DCR: .047
Bypass air: none.
Low idle: .083
Upper idle: .052
Main air body: .058
Main air horn: .039

At some point I had:
Idle tubes: .035
DCR: .047
Bypass air: none.
Low idle: .083
Upper idle: .052
Main air body: .043
Main air horn: .043

I didn't ran very well, but later on I discovered I had ignition issues. But in the mean time I also had enlarged the main air body to .055 to be more close to stock.
However, today I found out that it runs worse when warm. Cold it fires right up, but as soon as the chokeplate closes it shuts off.
Quadrajetpower did say: "Smaller main bleeds will richen the mixture, which should be fine for todays fuels."

So I'm afraid I'm running really lean. On top of that, this post shows a difference between small block and big block idle mixture screws. Obviously I have the wrong ones, so I have to turn them way out.

https://www.corvetteforum.com/forums/c3-tech-performance/4248854-rebuilding-a-1969-rebuildable-core-quadrajet-carb.html#post1598998287

I know there is a lot of mixing and matching done with remanufacturing carbs, but after some online investigation I think I'm fairly lucky with regard to the baseplate, body and airhorn. The parts I have look identical to original 1969 carbs which sometimes are photographed on forums.
Obviously I'm a novice regarding Q-jets, so I'll probably miss stuff. But I have time to experiment some.
And living in Europe it isn't easy to find a good core, that stuff is rare here.

Shiny:
Sounds like you have a good handle on it and got some good help.

I will follow your lead and verify my castings as I could also have a Frankencarb.  I'll also look at your link.

I have a 29240MD carb with a similar questionable pedigree and a bad performance history confused by other issues !!!!

So I'll watch for your updates.

I have been into my carb at least 3 times, with advice from Cliff and another knowledgeable carb guy on the PY Pontiac Forum.  My problem is a history of unstable idling and flooding.  I am currently replacing the gas tank to eliminate rust from the sending unit.  I am also going to address unstable timing by replacing disty springs/weights and the vibe damper.

My Buick carb is on a 350 Pontiac with a mild cam (Summit 2800) at 5800 ft. elevation.

Here are the last numbers I recorded.  They are different than yours so will be good to compare:

Upper Air Bleed      0.053
Down Channel      0.049
Lower Air Bleed      0.079
Bypass         0.089
Mixture Holes      0.090
Idle Tubes         0.035
Primary Jets           70
Primary Rods         44B
Secondary Rods          CH
Secondary Hanger         O
Power pump spring         6"  (Green or Black)

srb12:
I thought I had my ignition problems left behind, but unfortunately it still isn't resolved.

So I'll address that first. I have my old Holley installed in the meantime to make sure the other issues have resolved before installing the Q-jet again.

I have it on the bench now and will make the main air bleeds smaller.
I'm not sure if I also have to enlarge the down channel restriction little bit to .051 for today's fuels:

"https://www.motortrend.com/how-to/quick-tech-ethanol-friendly-q-jet-rebuild/
"We accomplish this by measuring the idle tubes and increasing their size by .002- to .003-inch. We generally then like to see the channel restriction between .050 and .055 inch. Your mixture screws should then allow for proper mixture control."
My idle tubes are already a little bit bigger than stock, so this might be correct then.

I also just noticed that my air horn is little bit warped, so I have to correct that first. I'll look around on this forum for tips.

I don't think we should compare each others carburetor specs, yours is a small block and you're on altitude. No clue how that should affect yours.

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