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17057231 or 17059232 on a 472

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Cadman-iac:
 So eventually I'm going to be using a '69 472 in a '56 Cadillac, but I'd prefer to use a newer carburetor on it with the APT.
  I have both of these carbs, 17057231, and 17059232, but they're calibrated for a 425, and both have the primary side POE system. Is that calibration acceptable for a 472, or would they need to be "tweaked" a bit, and if so, exactly where?
 I do have multiple original '69 Cadillac carbs, and if memory serves they do not use the POE system for the primary side.
 However I don't know if the specs for an early design would necessarily work on the later one due to design upgrades.
 Any thoughts on how to proceed?

 Rick

novadude:
I don't have any good advice on how to proceed, but I believe the 7029230 Cadillac carb (1969) did have the primary POE system.  I had one of these in my "parts carb" collection, and I remember it because this is the first time I had seen one with the extra tubes.

Cadman-iac:

--- Quote from: novadude on January 05, 2026, 05:36:06 AM ---I don't have any good advice on how to proceed, but I believe the 7029230 Cadillac carb (1969) did have the primary POE system.  I had one of these in my "parts carb" collection, and I remember it because this is the first time I had seen one with the extra tubes.

--- End quote ---

 Now I'll definitely need to have a look at my early carbs, I honestly don't remember any having the POE system in them.
 I've got I think either 3 or 4 sets of the POE tubes from various carbs, and I believe that they were all of the newer design, (relatively speaking),
 It's easy enough to tell since the discharge ports are highly visible in the top of the air horn.
 I'll report back once I've had a look.

 Just wanted to say that I'm not looking to use a carb specifically for the POE system, I don't know that it's necessary. I just wanted a newer model that can be easier to find in good condition, such as the two I've got now.
 I'm just not sure if the extra 47 cubic inches will require any recalibration of the 425 carbs, or if they're close enough in size and fuel requirements that they'll just be a bolt-on and go situation.

 Another reason I'm concerned is that the 305 and the 350 Chevrolet carbs are definitely calibrated differently, with only 45 cubic inches between them, so why wouldn't you need to recalibrate for the 425 to 472 swap?

 Thanks for your input, it's much appreciated.

 Rick

Kenth:
I´d say that any of the two will work fine on the 472 as is.
Remember a larger engine will "pull" harder thru the carb than a smaller engine thus the calibration for the smaller engine often is sufficient for a larger engine.
Some testing, driving and tip-in, will reveal nessecary modifications, if any symptoms shows.

And, POE arrived 1971 for Cadillac Qjets.
1971 POE was drilled right thru the choke housing wall for exit both primary and secondary when needed.
Later on only primary POE was used.

Cadman-iac:

--- Quote from: Kenth on January 05, 2026, 07:01:07 AM ---I´d say that any of the two will work fine on the 472 as is.
Remember a larger engine will "pull" harder thru the carb than a smaller engine thus the calibration for the smaller engine often is sufficient for a larger engine.
Some testing, driving and tip-in, will reveal nessecary modifications, if any symptoms shows.

And, POE arrived 1971 for Cadillac Qjets.
1971 POE was drilled right thru the choke housing wall for exit both primary and secondary when needed.
Later on only primary POE was used.

--- End quote ---

  That's encouraging, I'd like to just bolt on and go if possible. And I can see what you mean about the size difference.  The 425/472's being bigger than the 305/350's, the actual difference is a smaller percentage so theoretically shouldn't require much if any recalibration. Thanks for pointing that out.

 As for the first POE system, you wouldn't happen to have a picture of how they drilled the discharge ports to work with both halves of the carb would you?  That's really interesting to me.

 I can imagine that the secondary POE probably didn't work very well with it having to clear the "shelf" of the air horn at the front of the secondaries where the hanger and rods and the air bleed tubes are located, or am I not picturing it correctly?
 It's still fascinating to see how the carburetor developed over the years.

 Thanks for your help Kenth, I appreciate your input.

  Rick

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