If you haven't considered a carburetor spacer, here's something to keep in mind. They don't require much effort to install, generally have the potential to free up extra power, don't require any maintenance, and are pretty affordable. If you considered all the other aftermarket products on the market that offer the same power benefits, you wouldn't even be able to come close to the bang-for-the-buck that these spacers offer.
So what does a carburetor spacer do? In a nutshell, adding a carburetor spacer increases the intake plenum volume by creating a taller neck on the manifold. With the extra volume, the distance between the floor (bottom of the intake manifold) and the bottom of the carburetor is also increased. The extra distance allows for the intake mixture to straighten out. Along with the extra plenum volume, the intake runner volume is also increased, potentially allowing the engine to breathe more efficiently and ultimately make more power.
Considering the engine combination you've got is tuned correctly, it's safe to say that you're going to produce more top-end power while only taking away a little bottom-end grunt (think of a tunnel-ram manifold). Still, in high-revving engine combos that isn't necessarily a bad thing. Actually, reducing the plenum volume will give the engine more of an edge at lower rpm while taking away a bit of power up top in higher rpm. While open spacers add plenum volume, which can reduce low-end torque and extend the upper rpm range, a four-hole spacer will add low-end torque by increasing the air velocity. Of course, this is assuming the camshaft can help provide it.
Our experience with carb spacers isn't without proof either. In the past, the spacers have been a wolf in sheep's clothing, so to speak, and have landed us pretty solid numbers on some of our final dyno pulls. Take into account our three-way small-block shootout (Aug. '08). The Misfit 327 was impressive on pump gas, producing 380 hp. We thought that was all the little guy could muster up, until our comrades at the Westech dyno facility topped off our street mule with an open 2-inch spacer. The results showed an extra 11 ponies, making our final pull peak out at 391 hp.
So, in an effort to showcase what's available, we've compiled a list with detailed specs, including the price, dimensions, and what manifolds they fit. We've even listed which manufacturers offer a 4150-to-Dominator adapter plate. All said and done, the benefits vary by engine, based on various combinations, however there's a good chance something will be gained from it.
What We Did
Compiled a list of what's available in an easy-to-read format with the vital specs you're looking for.
They're affordable and a quick way to generate additional horsepower.
Starting at $15
These cloverleaf designs are offered for Dominator baseplates, this cloverleaf design promotes horsepower and torque in the mid-to-upper rpm range. These trick pieces are also available for throttle-body applications.
Notes: Comes complete, just install it.
Trick Flow Specialties