Has your taste in cars not changed since the early 70s? Think all these kids with their hoity-toity electric fuel injection don't have a gosh darn clue how easy they have it in the year 2021? The Holley 650 Double Pumper might be the performance carburetor for you. The choice to choose carburetors over fuel injection in your next project build is a bold and time-consuming ordeal if you choose to do so. But for purists and racing fans alike, there's nothing that beats the mechanical and organic feeling throttle response of a good old carb sitting under your engine bay.
But what exactly makes the 650 Double Pumper better than your run of the mill four-barrel carburetor? Well, there's a lot of corporate buzzwords flying around trying to make you think the 650 is the bee's knees. But let's do our best to sort through them to make sense of what's the real deal
Join us as we try and figure out if the Holly 650 Double Pumper Carburetor should have a home in your next project car.
Why Even Bother?
If you're born in a year after 1975, you may not even remember a time when carburetors were commonplace. In fact, you may be asking the question "Why the heck would I even consider using carburetors when port fuel and even direct injection does such a better job?"
Well, the answer to that will largely depend on who you talk to. Ask you average Midas, Meineke, or Pep-Boys shop tech if they're a fan of carburetors, they'd probably break out in sweats just thinking about them. Other people will swear that being able to tune air and fuel flow with a set of screwdrivers on the choke plate of a carburetor is easier and cheaper than fiddling around with engine computer diagnostics using expensive software to get the electric fuel injection to work correctly.
Why On Earth Is It Called A Double Pumper?
On paper, the Holly Double Pumper is a standard four-barrel carburetor that works in the same manner as parts from other companies like Edelbrock. The main difference, of course, is the inclusion of an extra accelerator pump arm at opposite corners of the carb assembly. This extra working action ensures an even fuel flow from the carb to the engine and then into the combustion chamber. This extra pump arm is also the telltale sign of a Holley Double pumper setup. Going with the doubles theme, there are also dual adjustable float bowls that can change the fuel flow with the turn of a flathead screwdriver.
All this clever tech means when you really stomp on it, the dual accelerator pump arms will ensure you don't even notice the difference between it and a fuel-injected engine. The car will just happily accept your throttle input and all the joyous revs that creates. It may not be V-Tec, but if the snore-fest of an explanation video is to be believed, it'll be even better. With a physical wire cable connecting the throttle to your right foot. It's bound to be more tactile fun than any V-Tec system.
It's Tune Time
If you're used to today's cars costing thousands of dollars for a proper tune, the Holley 650 Double Pumper must be like dream come true for you. Because not only is it easy to install, easy to fiddle with, and easy to remove again, it doesn't have to involve highly expensive computer software to make big power.
The amount of power this little gem can put out is dependant on the engine you fasten it to. Considering a four-barrel "Supercommando" carb on the Mopar 440 V8 in the Plymouth Superbird could make north of 450 horsepower without the aid of a second accelerator pump arm, we can only imagine a double pumper system could send that well beyond 500. Think you can tune your Holley 650 to make more? One of these carburetors can be yours for a very reasonable $470 on Amazon. You can even finance one for just $77 a month with an Amazon store credit card. With prices like that, you may be tempted to break out that bank card, but before you do let us hit you with some cold hard facts.
Is It Worth It?
Dave The Car Wizard is one of the most trusted mechanic Youtubers on the web, so when he tells you something is a bad idea, he's probably right. In June 2020, a customer of his brought in an LS swapped resto modded C3 Corvette, only this time, the engine had an Edelbrock carburetor, a prime competitor for the Holley 650 instead of fuel injection.
What the Wizard reveals could change your mind on hitting the checkout button on Amazon. You see, if you know the ins and outs of carburetors like the back of your hand, they can be wonderful tools to make insane power. But in a world where some young mechanics have never even seen a carbureted vehicle before, some shops won't even touch them.
So what have we learned here? Well, for one thing, if you thought the carburetor industry is dead, consider yourself disproven. Whether or not it's the right choice for you is one only you can make. But do feel free to let us know what you think about this debate on our Facebook page. We're itching to see what kind of carbureted setups you all have come up with.
Sources: Holley, Youtube.com/CarWizard