Although carburetors have been long extinct in production vehicles, in the world of the automotive hobbyist, their popularity endures. When you get right down to it there are many reasons in favor of a carbed setup, from tradition and that correct “vintage” vibe, to the relatively low cost and ease of installation and tuning. The bottom line is that carbs get the job done, and if correctly set up and tuned, perform very well. A four-barrel carb will get you on the road while requiring little more than winding in four bolts and connecting the fuel line and linkage to be ready to run.
Enthusiasts have more choices in carburetors today than ever before. At the low-buck end, some choose to bottom feed using cast-off OEM or used-up swap meet pieces, working mechanical magic to make them viable. For others, the game plan revolves around opening the box on a brand-new unit, and getting up and running with minimal hassle. Today’s aftermarket is chock-full of high-end monster-sized race-style carburetors that would have been hard to imagine just a few short decades ago. While these mixers have their place, a true driver street application benefits from a carb designed for just that application.
We took a detailed look at five new budget carburetors, all aimed at the street user. These carbs are all built with street calibrations, they come with a choke and vacuum or air-valve–regulated secondary operation, and are offered in sizing to meet the needs of moderate street engines. The features and configurations of the carbs vary, but the general theme running across the group is reliable and efficient street operation and value for the dollar.
Holley’s series of Street Avenger carbs have developed a following with performance enthusiasts since the original carbs were introduced nearly a decade ago. The idea was to provide a truly street-friendly version of Holley’s race-proven modular carb design. The emphasis in the Street Avenger line is making the carbs as reliable and goof-proof as possible, with enhanced street metering calibrations, while retaining the familiar tuning aspects that have made Holley famous. The latest of these carbs are the Aluminum Street Avengers, available in 570-, 670-, and 770-cfm ratings to suit most street applications. Owing to their aluminum construction, these carbs are substantially lighter than their traditional cast-zinc counterparts, saving about five pounds, and the aluminum holds its polished finish much longer for lasting good looks.
These carbs have a vacuum-secondary configuration, and come equipped with Holley’s quick-change vacuum diaphragm, allowing quick and easy secondary diaphragm spring changes for rapid recalibration of the secondary opening rate. The large sight glass and center-hung floats make float level calibration a simple process. Four-corner idle adjustment provides superior idle control with idle circuits built into both the primary and secondary sides of the carburetor, a feature normally found on higher-end or race units. To accommodate a variety of street installations, the carbs are equipped with a full complement of vacuum fittings, including PCV, brake booster, ported vacuum advance, and a manifold vacuum accessory port. If you are looking for a street-orientated carb in a familiar and traditional Holley configuration, the new Aluminum Street Avengers are right on target.
By the Numbers
Holley Aluminum Street Avenger
Rated Flow: 570, 670, 770 cfm
Secondary Type: Vacuum secondary with quick-change diaphragm
Mounting Flange: 4150/squarebore
Choke: Electric or manual
Fuel Metering: Primary and secondary metering block, primary power valve
Options: Accepts most Holley accesories
Special Features: Straight boosters, bowl sight glass, four-corner idle, blow-proof power valve, lightweight aluminum body
Street Price: From $359
The Aluminum Street Avenger...
The Aluminum Street Avenger comes with dual metering blocks, center-hung bowls, and four-corner idle adjustment as standard equipment. Throttle linkage is the familiar Holley arrangement, accepting the Ford transmission linkage, or the accessory Mopar throttle bracket.
These Holley carbs come through...
These Holley carbs come through with straight-leg boosters in the primary and secondary barrels, and fixed-orifice air bleeds. Holley spent considerable effort in dialing in the calibration, creating a fuel curve that caters to the street enthusiast who would rather not deal with the endless permutations of possible air bleed changes. This fixed air bleed arrangement is the same setup used in old-school Holley carbs for decades.
Stripped down, we can see...
Stripped down, we can see the Aluminum Street Avenger comes with the power valve enrichment circuit and accelerator pump on the primary side only, while the secondary side features a metering block with idle and main circuits.