Holley Carbs

[middleagecrazy]

Can anyone explain how Holley carburetor numbers work or what they mean.
They have list numbers ,manufacturers numbers......where can a guy find a list of these numbers so he may identity a carburetor.For example on Ebay there is a Holley listed as :

Holley 7249.....what is that? How can you determine the cfm from this?

I would like to find a small 4 BBl...around 390 cfm for a project.......but unless the seller speifies the cfm how would you detemine this? As you can see I know very little about these carbs but want to learn without buying a ton of books(for starters).Any and all information,what books to buy would be muchly appreciated.

[MagicRat]

Welcome to AF.

I am a big fan of Holley carbs. They are relatively simple, durable and extremely versatile. They can be tuned very easily to be used in a wide variety of situations.

They are not quite as sophisticated as most other 4 barrel carbs because their enrichment circuit (used to compensate for lower manifold vacuum) is relatively primitive compared to other cars, like the Rochester Quadrajet, Autolite etc. But they are so easy to tune that one can work around this.

Holley carbs usually come with 2 kinds of serial numbers, stamped in the choke blade housing. If the carb was factory original equipment on a car, it will have the car manufacturers part number on it. Ford sold millions of Holley carbs on their cars from the 1950's through to the 1980's all with Ford numbers.

If the carb was sold as an aftermarket item, it will have a 4-digit Holley part number. Usually, it is prefixed by a 'zero', like this ' 0-1850 '.

These Holley numbers are arbitrary. The number does not mean anything. You have to look it up in a Holley catalogue to figure out what it is. Go to this site and type in the part number into the search function and you will get information only if the carb number is still current. Lots of carb models have been discontinued. Otherwise, an older Holley book is useful.

http://www.holley.com/search.asp


Holley has made literally hundreds of distinct carb models, based on 5 basic designs.

These designs are:

The 4150 and 4160 design.
-These are 'square-bore' models, where alll 4 barrels are the same diameter.
The 4150 and 4160 differ only in the way the fuel metering is set up for the secondary barrels. The 4150 is easier to adjust the fuel mixture for the secondaries, but is slightly more expensive to buy.
They have been made in many sizes from 390 CFM to 850 CFM.

The 4165/4175 :
This is a 'spread-bore' design, there the primary barrels are smaller than the secondary barrels, similar to a Quardajet and Autolite carb. The idea is that they will give better fuel economy for ordinary on-road driving. But their throttle response is not as linear as a square-bore design. When you open the secondaries, you get a more sudden power increase than a square-bore. This is fine fo rthe street, but performance/racing applications favour the 'squarebore' design.
They have been made in sizes from 650 to 750 CFM

2300 design:
This is a 2-barrel carb, its pretty much identical to a 4150, but without the secondary barrels. They come in 350 and 500 cfm.

The 4500 "Dominator" design:
Huge race-only carb, 1050 or 1150 cfm. Not for street use.

The 4360 design:
Strange-looking carb intended as a bolt-on replacement for the Rochester Quadrajet. It is not based on the normal 'modular' Holley design and is not very popular, and typically are rated at 450 CFM.

The first two designs shown above are the most common and the ones most often used. They can be bought with side-hung or center-hung floar bowls. The side-hung are cheaper and better for off-road use. The center-hung is better for street use with lots of high-speed turns. But for most regular sue, yo uwill not notice a difference.

These designs can use vacuum or mechanical secondaries. Vacuum is best for street use. The mechanical secondaries (often called "double-pumpers" due to their use of 2 accelerator pumps) generally are better for high-rpm racing.

You can get single-feed or dual-feed fuel inlets..... dual is more useful for racing.... and mechanical or electric chokes. Electric chokes are more convenient but a bit more money.

The 390 CFM 4bbl:

What kind of engine do you want the 390 4barrel for? Holley also made 450 cfm 4bbl cars.

I bought one twenty years ago for use on an Edelbrock - modified 2.8 liter Chevy V6 (Still have it) The carb worked great. It is a model 0-8007, a '4160' design, 390 cfm with side-hung bowls and vacuum secondaries.

Jetting:

But, like most Holley's, my 390 CFM carb was jetted a bit too rich for street use. I had to convert it to a 4150 design and change the jets on all 4 barrels. It came with #51 jets, and I dropped it down to #49 jets, then it ran perfectly.

FWIW I have had to lean-out all my Holley carbs just a bit. I bought a 750 4bbl Holley carb (4160 design) with vacuum secondaries. (I bought this in Edmonton, for use on a modified Oldsmobile 455)
It had #73 jets. I dropped it to #71 on the primary side, but left the secondary side alone. Now I get efficient cruising. It would be nice to lean out the secondary side, too but I did not have the time to do so.

BTW, a larger carb, like a 750 means that you will not be using the secondaies often. But with a 390 carb, I find the secondaries are open a lot of the time, due to the lower power of the engine. So it's more important that the secondaries on a 390 are jetted right.

Finally, your Ebay carb number does not show up on any of my Holley books so I do not know what it is. I will look further into this.

Ebay search:

I just searched for "Holley 8007" and I came up with six 390-CFM carbs for sale:

http://shop.ebay.com/?_from=R40&_trk...All-Categories

[middleagecrazy]

Thanks MagicRat for all your information-I found it
extremely helpful-saved hours of digging.
Can you recommend which book would be the most helpful in rebuilding and tuning a Holley Carb.?
Heres my project:
I wanting to shoehorn a 5.9L Magnum into my 87 Dakota Shortbox. At present its has a carbed. 3.9 V6. and until I find a decent 5.9 was maybe going to squeeze a little more power out of it by adding a bigger carb and maybe some headers-if I could find these items cheap.One problem is that it has a 2BBL manifold and from what I have read a 4BBL manifold for the 3.9 was at one time available but now are about as rare as chicken teeth- so maybe adapt a small 4BBL carb. with an adapter(?).
Wonder if a spreadbore work?


So.......that's my hopes,dreams,ambitions..........

I welcome your thoughts.

[MagicRat]

This is the Holley book I have. It includes a step by step rebuild with pictures as well as lots of information:
http://www.amazon.com/Holley-Carbure.../dp/1884089283

FWIW I think that adapting a 4 barrel carb to the 3.9 would not work well. There would simply be a huge mismatch on the throttle body. A Holley 2300 series carb might work.....if the bolt pattern is compatible and the ports in the top of the manifold are big enough.