Packard Forum Index » V-8 (1955-56)

I have a 3 carbs off of different '55s. One is a rochester, and two are GM carbs. Is one better than the other? Why did Packard's have 2 different carbs?

Packard tried to have at least two suppliers of everything so that a strike, fire or calamity at one plant would not halt production.

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You have me confused. Rochester is a division of GM.

BH,

2 of the carbs Say "GM" on them. The other says "Rochester"

Are they all the same?

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Are the metal tags still on the carbs, and do they have the same Packard numbers?

Great detail shots, Don.

Unfortunately, I can't recall that detail from any of my V8s, and they're all stored offsite and inaccessible - thanks to the long, brutal winter, here.

In spite of that difference, those two carbs are from the same supplier, but they could be from different years and/or applications. The 4-Jet was produced from 1952 to 1967, but changed quite a bit over that span.

Back in 55-56, a model number was stamped on a tag attached to an air horn screw, but those tags were often thoughtlessly discarded in the course of service. Not sure when they started stamping the last 4 digits of the model number into one corner of the air horn. For a while, some carbs had both a tag and stamped number.

One of your pics shows part of a tag - give us the number from that tag.

In the absence of a model number, a carb expert might have to go so far as to disassemble the carb and check key components against known models to exactly identify it.

The 55s have sight plugs in the fuel bowl casting to check fuel level, but those were eliminated for 56. The 56s have a larger diameter accelerator pump plunger and correspondingly different fuel bowl casting. Mind you, that's just a couple of examples. There are also differences within any given model year, for different engine applications.

The 1955s with the 352 V-8 were equipped with Rochester carburtors and Delco electrics. The 320 V-8s were equipped with Carter carburetors and Auto Lite electrics.

(o{}o)

This is the tag on the Rochester Carb.

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This is the tag on the GM Carb:

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Well, both tags show the correct model number for a 55 352 motor.

I still don't know why the 'ROCHESTER' vs. 'GM' cast in the air horn.

I've read that that, in later years, Carter actually built QuadraJet units (successor to the 4GC) under license, as a secondary source for GM. Those units have "MFD. BY CARTER CARBURETOR FOR GMC" cast into the fuel bowl, but all parts were completely interchangeable.

Perhaps there was a similar arrangement for the 4GC line, but I've never seen anything to that effect.