Packard Forum Index » Modification Discussion

Will this. Holly carb .. The demon.

Work for 55.56 intake manifold.

Or do you need the adapter.

I believe the air cleaner can be modified to work.

Does the square make a difference.. Where Packard had 4 holes in intake.

Of coarse. Possible to mill a square in Packard intake..

Then there is this.
holley.com/products/fuel_systems/fuel_in ... el_systems/sniper_efi/parts/550-510

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You will need an adaptor plate to go from the small bolt pattern on the manifold to the larger pattern on the carburetor. Also, you will need to get the model of the Holley with the CFM to match your engine size. Throttle and transmission linkage will need to be devised. Does the Holley have ported and manifold vacuum ports? The Packard distributor uses ported vacuum to operate the vacuum chamber. Also, an aftermarket air cleaner may be required due to the size difference between the the original carburetor and the Holley. I have had good luck using Edelbrock carburetors. They come in a variety of CFMs and are highly tunable. Hope this helps.

Jw.

Thanks.

The holly has 2 cfms

625 and 750.

I read about the edelbrock. Its so wide... Looks like a crab.

Yes..
The holly has vacuum ports like edelbrock.

Timed and straight vacuum.

You need to find the CFM of the orignal carb and replace it with one that has close to the same CFM, unless you have modified the engine.

Reuilding the original equipment is usually the best course.

Linkage can be a real headache.

For what its worth, it seems a CFM rating for the specific 4GC carbs Packard used are not well publicized. I did find a 20 year old discussion on a hot rodder forum that mentions the 4GC came in 3 sizes and gave some dimensions. I guess to find the actual CFM number you will need to compare the bore and venturi diameters to the Packard given specs. A similar response was on a 15 year old post in the HAMB forum.

Here is the post containing the size info along with a number for an air cleaner adapter. Maybe there is something similar that could go the other way to allow use of the stock cleaner. Did not see any info on adapters for the mounting to intake manifold.

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Thanks h.

I did call ross.

He did a computer check. And said the 625 cfm is plenty.

The other posts on the edelbrock.

Used for the 55.56 cars 625 cfm.
Model 1406.

The holly leakage uses the stud like Packard.

Where I believe the edelbrock uses a cable.

Air filter adapter.

Summit has it .. As does holly

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Quote:

Best advice you'll ever get.

Core carbs are still thick on the ground. PM me if you need one.

jack vines