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Holley and NASCAR: A Performance Marriage That’s Still Going Strong

Events

Jim Hill

11/12/2019

10 min read

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Holley and NASCAR: A Performance Marriage That’s Still Going Strong

Holley and NASCAR: A Performance Marriage That’s Still Going Strong

Jim Hill

11/12/2019

10 min read

The close alliance between NASCAR and Holley Performance Products goes beyond a mere business relationship. In fact, it began in the days of Bill France Sr., known as “Big Bill,” a racer and one of the founders of NASCAR. This was back when Holley was called Holley Carburetor Company. It was France who created the deal that made Holley the one and only carburetor used in NASCAR. Although legal paperwork later wrapped up the deal, it was originally just a handshake that sealed it.

Even though this deal was reached in 1969, the use of Holley carburetors in NASCAR actually dates back to 1957. Fords with the 312 CID Y-block V-8 were so equipped, as NASCAR rules called for “strictly stock.” That meant everything, especially a part as critical to performance as a carburetor.

Holley had been working hard with Ford and Chrysler to create high-performance carburetors capable of delivering the power favored by big-block V-8s entering the Grand National Division (today’s Cup cars). Single 4150 setups were used on Ford 427 FE engines and Chrysler 426 Hemi, and the occasional big-block Chevy 427 engine. The needs of NASCAR racers provided the genesis for the Holley Model 4500 Dominator. This carburetor would come to dominate all forms of racing into the 21st century. The rough-and-tumble late-1960s horsepower wars in NASCAR unleashed the king of the hill, the celebrated Holley Model 4500 Dominator. This was the largest carburetor ever designed, both in its airflow capacity—1,050 cfm—as well as in physical dimensions. The 4500 required an intake manifold with a whole new throttle-plate bolt pattern, considerably larger than the familiar Holley Model 4150 base. The Dominator also came with a pair of accelerator pumps—primary and secondary—for immediate throttle response. Race models were made without provisions on the primary side for a choke assembly, while later street versions had this. The rest of the 4500 was pretty much like a supersized 4150. Float bowls were cathedral style, with float height adjustments via a sight plug. They used the same main jets except for their much larger, flowed sizes. Also the throttle linkage had no provisions for automatic-transmission kick-down.

Even when NASCAR went to a maximum displacement of 358 cubic inches, Holley still powered racers like Buddy Baker to victory and the NASCAR record books. The 4500 Dominator was too good. NASCAR rulemakers soon began working on ways to back off the brute power that engines were able to make with this carburetor. For example, 4500 bore restrictors were used to reduce the air/fuel flow, and different sizes were tried. One industrious race team made their own restrictors and even passed tech—until the driver went suspiciously faster than his previous best. A second look revealed the bore restrictors were made from wax, which melted away quickly, adding nearly 10 mph to the car’s qualifying speed.

Next came restrictor plates of steadily smaller bore size, until the teams finally gave up on the 4500. Rules were adjusted again, and the Model 4150 became the choice in a more conservative 830-cfm size. When NASCAR replaced carburetors with fuel injection for the 2012 racing season, Holley developed a throttle body for the specific series. This continues the performance fuel-delivery role that Holley has played in NASCAR racing for 50 years. In spite of all the back-and-forth play between race teams and NASCAR rulemakers, Holley fuel delivery has remained the one constant. Today, Holley makes throttle body units used in specific NASCAR racing series, as well as Holley HP EFI systems in ARCA race cars. Teams campaigning with Ilmor Racing Engines in the NASCAR truck series also utilize Holley HP ECUs.