Since changing the intake manifold and carburetor may not seem like a basic operation to some, what then are the basics when it comes to adding performance? Maybe we should start with a better-than-average set of spark plugs or some octane boost. These things might be basic, but how much performance will these changes yield? Sure, that stuff helps and it all adds up in the end, but to achieve a full step in the performance direction we have to get dirty. We also have to spend some of that hard-earned cash. So what is cost-effective performance?
With varying ideas on this subject, most everyone will place changing the intake and carb close to the top of the list. It makes perfect sense that additional fuel and air, fed through ports designed to get them into the cylinders more efficiently, will do nothing but add horsepower, increase fuel economy, and add to the engine's life. This depends on the right combination to maximize performance on specific engines. The size of the carburetor and the intake design are pivotal choices that need to be nailed down before any costly decisions are made. Given the fact that we have many choices of performance parts companies, everyone should shop around to find out which companies have stood the test of time and why.
Holley Performance is one of those companies. Not only does Holley stand behind your choice, they offer virtually hundreds of carburetor and manifold configurations to their customers. The amount of fine-tuning that can be done to just about any of their carburetors means they have something to accommodate any carbureted car or truck.
For this upgrade we wanted to install the right amount of performance to make our daily driven '67 Chevelle wagon move with increased fuel economy and power. We also wanted to find parts that will easily be adapted to a fresher powerplant sometime in the near future. To achieve this with a minimal amount of fuss, one phone call was made to Holley's tech line to find out what their experts recommend.
The information we received was, for an all-around increase in performance (meaning fuel mileage and power) for a stock-to-mild small-block with a horsepower rating up to 300, Holley's new Street Avenger 570-cfm carburetor with their dual-plane Street Dominator high-rise intake manifold were recommended. The Street Dominator is designed specifically for good power through the low- and mid-rpm range, all the way to 7,200 rpm. The new Street Avenger carburetor comes with adjustable vacuum secondaries to help boost power or fuel economy (depending on how heavy of a right foot you have).
A power valve with a million-mile warranty is also standard, and it's all backed by Holley's claim of a, "street ready out of the box, no fuss installation." Aside from a few trips to the parts store for things like vacuum hose, a fuel filter, a new belt, an alternator bracket, hose clamps, a carb spring, and various nuts and bolts, this was just what Holley said. The power and fuel economy was also noticed immediately. The fuel consumption went from around 12 mpg to 15 mph. That's not bad considering the go-pedal is far more responsive than before (which has made it hard to keep from slammin' it to the floor after the green light comes on).
With the basic upgrade completed on the wagon, it will soon find its way onto our dyno for horsepower and torque results after further low-buck performance upgrades. The future changes will be designed to help our cruiser work more efficiently as a daily driven commuter. Until then, check out this "basic" installation and look for some of the little things that will help you achieve the same results.