Do Holley carburetors always need adjusting?
- Arron Johnson
- Dec 15, 2014
- 4 min read
This one has always puzzled us. Almost every muscle car came from the factory with a Holley carb or Carb(s) on it. That includes many of the Shelby's, Cobra's, Tri-Power Vettes, some of the big block Chevelles, Six Pack Mopars, Ford "6V" systems, first and second generation Z/28's, and even motor homes, trucks and commercial delivery vehicles came with factory installed Holley carbs and none of them ever have any problems. Most of these cars and trucks are still running today, so it would seem funny that Holley's got this bad reputation of always going out of adjustment or needing to be tuned all of the time. That is SO far out in left field, it isn't even funny. The image at the upper right shows an original Shelby GT-500 with it's original pair of Holleys on it.
We choose Holley carbs on most of the performance cars and engines we build because they work! What do you see on NASCARs? What do you see on Pro-Stocker's? What do you see on the new Shelby Cobra's? ALL Holley's. Do you think GM, Ford AND Chrysler, AND Shelby, AND NASCAR, and all of the million other performance engine and car builder's out there are stupid? Ever see a NASCAR have to come into the pits because the carb needed re-adjusting? The image to the right shows a NASCAR engine with a Holley carburetor on it.
Here's a 427 Tri Power Vette engine with guess what? Holleys on it.
And here's Dodge's version of a 6 pack, with 3 Holleys.
And here's the mighty 426 Hemi with two Holleys on it.
And here's one on an early Z/28 engine.
So what about other carburetors, such as an Edelbrock? I am friend's with the entire Edelbrock clan, not to mention I'm Edelbrock's official installation video host, and I can tell you first hand that Vic himself will tell you, for a serious performance engine, you need a Holley. He's not about to pull the wool over your eyes and have you buy one of his carbs for your nasty engine and then not have it run as strong as it could. Sure, an Edelbrock (AFB) carb will run nice, but not AS nice as it could on something that is more serious with a Holley on it. Edelbrock's all about quality and happy customer's. A customer with a carb that just can't cut-it, isn't a good sale for the next items he (or she) may need, not to mention, Edelbrock caters to the masses who have milder engines and cars, not the small group of people who have wild engines in seriously performing cars . Again, don't get me wrong, there's nothing wrong with an Edelbrock carb, which is a re-make of a Carter AFB that is actually made by Weber, hence the WEBER name on the side of the carbs and the "W" markings all over them. For a stock or basic performance engine, an Edelbrock carb is just fine.
We prefer Holley's, or Holley DESIGNED type carburetors on our nasty engines though, such as Quick Fuel Technology, and none of them ever need constant adjusting, just like none of the original muscle cars that came with Holleys needed "constant" adjusting. ALL of the needle and seats in them work similarly. ALL of the floats work similarly, and so on. In fact, carbs like the Quadrajet, Edelbrock (Carter AFB types) and so on are actually much more complicated in design than any Holley because Holley's don't use things like metering rods and jet combinations, and don't need to be fully disassembled to change things like the needle and seat, an accelerator pump, a main jet, a power valve, etc. It's exactly why race teams and serious cars use them instead of other types of carbs.
The main issue with Holleys having problems is dirt! But this is true for ANY type, or brand, of carb. 99% of the time, the problem guys have with their Holleys is dirt in the needle and seat which prevents it from shutting-off the fuel supply, so what happens is; gas over fills the bowl which causes it to gurgle-up through the vent tube and run down the throat of the carb causing it to flood and run terrible. That's not the carb's fault... it's the owner's fault. It only takes a tiny little particle to cause that needle and seat to not shut-off, so as the engine is running, fuel flows into the bowl faster than the engine can use it (most common when it's idling) because that needle and seat isn't completely shutting off and it floods, which causes it to run terrible. But again, it's not the carb's fault. Most other brands and types of carbs use VERY similar types of needle and seats and they don't need additional adjusting anymore than any Holley does.
If you want to learn more about this kind of stuff, in much greater detail, be sure to check out our Auto Shop Videosseries by clicking HERE. We have one titled "Performance Carburetors" that covers all of this kind of stuff and MUCH more. These make great Christmas, Father's Day and Birthday gifts!
Comments