Thanks Dennis- sounds like no way I can make that carb work right with that limitation.
I'll try my 400 AFB- was reluctant to originally because it was kind of a nasty old core before I freshened it up and I was never able to get all
of the 4 jets out due to heavy corrosion.

Put together a 69 Dart w/ Clifford Headers, 3.55 Sure Grip, Reverse Manual Valve Body, 4 bl. Intake an an old AFB which I rebuilt orig. from a 65 Imperial. The car runs pretty good but when I step on it WOT it bogs.
I'm wondering if this is because it does not have a mechanical secondary valve (not missing- different design which doesn't incorporate it).
I have a later 9410 AFB 400 CFM which has the valve which I was thinking of switching and trying.
Any thoughts ???

Thanks again Dennis!
Any chance you would want to part with your 400 AFB
which is probably in much better shape than mine?
Forgot to say that the reason I wanted to be able to remove
the jets is to have the option to use others, as this is going
to be a street and bracket racer.
Wanted to be able to use other jets w/o having to drill
mine (w/ chips)

Ah yes. That's an oddball carb on several fronts. Its a small 4-barrel made to run on a BIG engine, in a BIG car, providing a lot of low-end torque and adequate high-speed power. It also has a smaller-than-normal air horn (same size as the large 2-bbl used on 383 engines) so finding an air cleaner that works will be interesting. There's no secondary air damper because its intended to be on an engine almost twice the displacement of a slant-6, which can handle the sudden opening of all 4 barrels. It does have mechanical secondaries, but the issue is that it has no air damper to bring them on-line slowly. I wouldn't think you could ever tune it to run well on a small engine. I'd go with the 9410.

Forgot to say that the reason I wanted to be able to remove
the jets is to have the option to use others, as this is going
to be a street and bracket racer.
Wanted to be able to use other jets w/o having to drill
mine (w/ chips)

Were these carbs used on 273 Commandos too? I had one on my 318 (used the original Commando air cleaner and crinkle covers too), but the bog wouldn't go away even though it ran sweet otherwise.

Hey Dennis-
How about you list the Duster on Ebag "Buy It Now"
for $4000, perfect running car minus only the carb.
Then send said carb to me.
I get a free carb, you get an extra $500.
Hey the joys on being a tycoon!
Seriously though, thanks for all the advice.
Looks like I'll never be happy w/ the oddball carb
and if I spray it, it even sounds dangerous.

Thanks Dennis-
after digging out my 9410 AFB, I found the metering rods
and springs are missing.
Can you or anyone tell me what size rods were in that
carb, or in the equivalent 4294S carb you have on your car?
Also, do you know the orig. sizes of the primary jets?