Cowl hood scoop7/6/2023 With the use of available flow bench equipment of the era, Jenkins figured out that the hood scoop opening should be as small as practical. To compensate, Jenkins carefully reworked each carburetor. As you might expect, the back carburetor had little if any air velocity over it, but the front carburetor was still affected by the on-rushing air. Initially, Jenkins attempted to reduce air speed and turbulence over the carburetors by modifying the internal walls of the scoop with an elaborate series of sheet aluminum panels. Because of this, engine placement in the chassis and the overall height of the intake manifold plenum and carburetors were critical to the scoop layout. Hood scoop height was a conundrum because NHRA Pro Stock rules dictated scoop height. This setup slowed the air upon entering the front opening, allowing for recovery within the hood scoop plenum. For example, the scoop sidewalls diverged toward the rear (seven degrees of slope, front to rear, according to Jenkins). The Jenkins’ scoop was innovative for the time and heavily influenced hood scoop technology for years after. This would eventually evolve into a more-sophisticated hood scoop which made its debut on Jenkins’ last Vega Pro Stock car. Case-in-point is the late Bill Jenkins’ experimentation that eventually led to the renowned “Grump Lump,” a box-style scoop with a rear entrance. Others in the racing biz were paying close attention to the importance of hood scoops. In contrast to the scoop on the Cobalt is the low profile design found on this Super Modified Cavalier (mandated by the NHRA rules for Competition Eliminator). Placing the scoop in direct line with moving air improved the “ram” factor. A scoop with an opening flush with the hood surface was essentially mounted in dead air. Instead, the inlet was raised slightly to account for the air flow passing over the nose and hood of the car. With this arrangement, the opening of the scoop wasn’t flush with the top of the hood. These first Mopar-designed scoops relied on the “boundary layer” principle. A year or so later, a slightly more sophisticated, but equally large scoop appeared on 1969 440 Six Packcars. Factory race cars, such as the 1968 Super Stock Darts and Barracudas, incorporated large forward-facing scoops. The Mopar bunch took the direct approach to cold air systems. The early beginnings of Pro Stock brought us an abundance of different hood scoop designs, and to a certain degree, the influences came straight from Chrysler Corp. They weren’t truly functional hood scoops. Plenty of those cars came from the factory with cold air induction packages, and many of these cold air packages were for looks only. Almost simultaneously, muscle cars became a hot commodity. With racers struggling to find tenths (or even hundredths) of seconds, fresh air induction suddenly became important. For instance, notice the scoop design on this SS/Modified Cobalt. The diversity in hood scoops is remarkable. Instead they had an array of open injector stacks poking through the hood top.īut then, Super Stock quickly became the rage. Back in the day, “real” race cars didn’t have hood scoops.
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