We've known for a long time that Superior Automotive in Anaheim, California, is a gold mine for Ford high-performance expertise. The folks at Superior Automotive work on all kinds of American muscle, but there's always something interesting going on from a Ford-performance perspective whenever we pay them a visit. From garden-variety Mustangs to the more esoteric visitors-such as a '48 Mercury convertible with a 460 conversion-on any given day, a visit to Superior always makes us feel like kids in a hobby shop.

In issues past, we visited the in-house carb shop and came away with extra horsepower. With more than 40 years of experience, Don Spaccarotella is the apostle of horsepower at the carb shop. He's especially adroit at resurrecting basket-case Holley four-barrel carbs. This time, we thought we'd throw him a curveball and see if he could get anything out of a brand-new Holley carb.

This is our new 650-cfm Holley double-pumper carb. With the car strapped onto the rollers, the idle is adjusted prior to the first pull.

Superior Automotive's Don Spaccarotella runs the '69 Mustang through the gears, settling in Fourth before the throttle is nailed, while carefully watching both the rpm and the air/fuel ratio. Several pulls were taken to ensure repeatability and to make sure there were no major problems with our project car.

The new Holley four-barrel is a 650-cfm unit sitting atop a fresh 351 Windsor. The double-pumper carb has a mechanical secondary, and the only alteration is that the choke has been wired open. The carb has about 2,000 miles on it, and the engine runs like gangbusters. Holley knows what it's doing when it comes to building carburetors, and a new Holley four-barrel will usually run fine right out of the box provided it's appropriately sized to the engine. Such is the case with our carburetor.

When we approached Superior with the idea of throwing Spaccarotella the new carb curveball, the company agreed to the story. Its employees have confidence in their man and know he will deliver. We wanted new baseline figures before the carburetor was modified and then a second session on the Dynojet to measure the result. To eliminate as many variables as possible, our test used the same Dynojet on the same day, with the same operator. Much of what Spaccarotella does is confidential, but if you send Superior your carb, the company can modify it, new or used.

Follow us to the Dynojet at Superior to see if Spaccarotella can squeak a few more ponies out of a new carb.

Normally, for a performance rebuild, the carb is completely disassembled and soaked in solvent for cleaning. Because the carburetor is new, Spaccarotella says he won't remove it from the engine. The central body of the carb remains in place, while various components are removed and replaced. Here, the rear float bowl is drained into a receptacle designed specifically for this purpose.

With the float bowl empty, disassembly begins. Here, the four float-bowl retaining bolts are removed.

Next, the float bowl and the metering block sandwiched between the float bowl and main body are removed. The float levels are fine; Spaccarotella is interested in the metering blocks. P