Holley History: 50 Years of Fuel Delivery

By: Jim Hill | 01/01/2020 < Back to Motor Life Home

It’s hard to believe that iconic Holley electric fuel pumps have been fueling race cars and street performance vehicles for 50 years! Although almost a half-century old, these trusted fuel-delivery products have remained cutting-edge technology for both carburetors and modern electronic fuel injection. There’s a Holley electric pump for any performance vehicle, from 6-second Pro Stocks to cruise-night restomods. It all began in 1970, when Holley answered the call to remedy a problem that racers were encountering in the Pro Stock category. 

Racers were flocking to the newly created NHRA and AHRA Pro Stock category. In those days, Pro Stock car counts at major events were 30-40 entries trying to qualify for a 16-car field. The basic Pro Stock formula was simple: fully modified engines, 2x4 carburetor systems using gasoline only, and a hoodscoop. The 7 lbs per cubic inch displacement weight break made big-block engines mandatory. The Chevy 427, Ford FE 427 and SOHC 427, Chrysler 426 Hemi and occasional Pontiac tunnel-port 421 were popular choices. Body styles favored the ponycar chassis: Camaro, Mustang and Firebird.

Problems arose when the dual-carb setup experienced both fuel pressure and volume problems with existing fuel-delivery systems. Most racers were using older electric pumps from Stewart-Warner, with two or more pumps mounted at the rear of the car, but the fuel demands of big-block engines running 7,000-plus rpm proved to be more than they could handle. 

Holley engineers set their sights on creating an electrically powered pump capable of providing adequate fuel volume for a pair of thirsty four-barrels on a tunnel-ram intake manifold at 7,000-8,000 rpm. Since the market was moving toward bigger carburetors and higher engine speeds, they elected to build a substantial margin of fuel pressure and volume into the new pump. This opened up an entirely new market for Holley.

The new Holley electric pump was engineered to flow 110-plus gallons per hour (GPH) at 6 to 9 pounds per square inch (PSI) of pressure. It had a rotary-vane–type pump design made from stainless steel with precision-machined rotor-vane slots. A constant-speed electric motor would power the pump and fuel would cool and lubricate it. A cast-aluminum pump housing was selected for strength and heat dissipation. While twin pumps were commonly used, the new Holley pump was designed as a solo application.

Holley aftermarket product marketing elected to name the new electric pump the Holley GPH-110 for its stout 110 GPH output. The high-output race pump was initially painted red, along with its adjustable pressure regulator. After a street version with an internally preset 7 PSI was created, the paint colors were reversed and the race pump was painted blue. That earned it the nickname “blue pump.” 

One issue did surface early in development. The Holley pump produced more fuel pressure than was needed. Typically 7 to 71/2 PSI being ideal, but above that, the carburetor metering system was disrupted. Holley resolved the issue with an external fuel-pressure regulator, adjustable to the exact pressure desired. Prototype pumps were built and application issues explored. One field-testing session took place at Milan Dragway in Michigan with local racer Wally Booth. A successful Super Stock racer, Wally was already competing in Pro Stock with his 1968 Chevy Camaro with race partner and engine builder, Dick Arons. Wally had removed his twin Stewart-Warner pumps and installed one new Holley electric pump. He also installed the adjustable Holley pressure regulator and a fuel-pressure gauge, setting it to 7 PSI for the Holley R-4224, 660-cfm “center squirter” carburetors he was using. Wally, Dick and crewmen Gordy Foust and Dave Tratechaud joined Holley project engineers one spring morning. After warming the big-block engine, Wally warmed the tires with a burnout, then staged. At 6,000 rpm, the Camaro picked up both front wheels in the air through first gear. The first run was a 10.08-second elapsed time at 132.44 mph. After chassis tuning and engine adjustments, two more runs were made, with a best 9.95 e.t. at 134.23 mph. While those numbers seem slow by today’s Pro Stock standards, they were at the top for the day. More importantly, the new Holley pump performed exactly as expected. After production samples were made and quality control checks performed, production began at Holley’s Bowling Green, Kentucky, plant. Pumps were sent out for testing to top Pro Stock racers Bill Jenkins and Don Nicholson. Both reported excellent results running the new Holley pump and regulator in open competition and match races. Wally, Bill, and Don later appeared in Holley advertising endorsing their use of the new Holley pumps. Bill installed a Holley GPH-110 pump and regulator on his new small-block Chevy-powered Vega, the car that turned Pro Stock racing upside-down in 1972. Bill and his Vega also appeared in a Holley ad, telling all why he believed in the Holley electric pump. The Holley blue pump became the overwhelming favorite of not only Pro Stock racers, but also those embracing Pro Stock technology for Super Stock, Modified and Competition Eliminators, taking advantage of the deluge of technical advancements in carburetor and fuel-delivery technology at the time. Holley has continued to refine and re-engineer the GPH-110 pump as needed and add many new fuel-system products to its product line over the years.

Pro Stock became part of big-show national event drag racing, and Holley was there to help the way with their groundbreaking and industry game-changing fuel system solutions.

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