OK, so let’s get down to it. The new Holley Screamin’ Demon carbs aren’t all that out of the ordinary when it comes to the Holley family lineup, as they feature a familiar 4-barrel 4150 platform. They do, however, come with a range of 650cfm up to 850cfm, perfect for mid-range power applications and very typical for what may be found in the weekend warrior’s garage. Most of these carburetors are available with mechanical secondaries. But with the 750cfm Screamin’ Demons, now users have a vacuum option.
Installation and Set Up
One of the best things about this product is the ease of installation. Demon isn’t trying to reinvent the wheel here—there’s nothing unusual for a 4150 platform. First, understand that most intake manifolds come ready to accept this platform or can be modified with ease. Once the carb is in place on the manifold, there are only a few other necessary items before the Holley Screamin’ Demon is up and running.
Now, this series of carburetor comes without any choke options available. So, you won’t have to worry about that step during the installation. Hooking up the throttle cable and return spring is as simple as tightening up a few bolts; again, nothing out of the ordinary here. The same thing goes for setting up the fuel lines.
However, it’s worth noting that the throttle lever itself is all new in design and works with Ford and 700r4 and Chrysler kick-downs. This is a nice feature, and it makes the Holley Screamin’ Demon an even more versatile pick at the local speed shop. Tuning this type of carb is as simple as the installation. Like all 4150 carbs, idler screws are used to dial in the fuel to air ratio. The float bowls feature dual sight glass windows on either side, which are awesome for setting the proper float level.
Another cool feature is that the secondaries are set up with a notched float and jet extensions, helping to prevent fuel starvation during hard launches. Having this feature right out of the box saves shop owners the time of having to pull the carburetor apart to make these mods. But don’t take our word for it—take his!
Already Held on High by the Best
“Drag racer’s want to do it right, and these new Screamin’ Demons make our lives easier,” explained Bill Cannon out of Selbyville Delaware, a renowned engine builder and truly one of the greats in the industry. He’s been building engines at his shop since 1984, but his hands have been at work since he was 12. As for Demon carbs, well, they’ve been a preferred line for Cannon the past two decades because he feels they outflow even the biggest names, and do so right out of the box.
For him, another nice feature is the convenience factor. Demon has a reputation of producing track-ready carbs and this product follows that trend, with its beefy secondaries and ease of installation. And the fact that the Demon lineup is part of the Holley family of brands is icing on the cake. “Holley is the best at what they do. Now that they’ve got the [Screamin’] Demon, they can only get better,” added Cannon.
The combination of simplicity and added features is what makes the Screamin’ Demon special. They are incredibly easy to set up and keep gearheads from having to pull the carb apart to dial it in track side. With a retail average that hangs right around $500, they really are something to write home about. “The Screamin’ Demon is a great carb and I can’t wait to get my hands on one for myself,” concluded Cannon.