After switching to Holley's Ultra XP carburetors, Nostalgia Super Stock racer Doug Duell is well on his way to becoming the 2013 NMCA Nostalgia Super Stock Champion. Duell recently swapped out the carburetors he was using in his B/FX 1964 Plymouth Fury station wagon, for a set of Holley 750 CFM Ultra XP carburetors. So far, the combination of his racing experience with added power from Holley, allowed Duell to win the first three NMCA events in Bradenton, FL., Atlanta, GA., and Joliet, IL, along with a second runner up finish at the fourth event in Bowling Green, KY. “I needed to pick a little more power from the engine setup I had last year,” says Duell. “My engine builder thought the Holley Ultra XP's would do the trick." 

Duell's Plymouth is powered by a 540 cubic inch Chrysler big-block Wedge, built by Indy Cylinder Head, and uses an A-727 TorqueFlite automatic. He began the year testing in Bowling Green, KY with the new carbs. After only changing the jets a few sizes and some minor tuning modifications, Doug was impressed with the performance and enhancements the Holley Ultra XP carbs made. "First thing I noticed, my 60-foot time went from 1.33 to 1.29 seconds," he says. "The engine idled better and was also easier to tune. With the better 60-foot times my reaction times also got much better.” The station wagon runs in a 9.50 second ET index. "I can easily run that with a best time of 9.39 at 144 mph," he says. "Not bad for a station wagon!” 

Holley Ultra XP carburetors have many benefits and upgrades that made it perfect for helping Duell’s Plymouth gain that extra performance edge. Made in the U.S.A. the Ultra XP's are 38 percent lighter, and incorporate a new fuel bowl design that has 20 percent more fuel capacity to eliminate fuel starvation under hard acceleration. The Ultra XP's also feature an upgraded base-plate made from lightweight 6061T-6 billet aluminum, and uses a race-only style throttle lever that eliminates all the unnecessary street attachment points and tangs. 

Holley also streamlined the Ultra XP carbs to improve airflow and make them easier to tune quickly at the track. For example, the air bleeds on the main body are moved outward, allowing for smoother airflow from the top of the carburetor into the venturi. The carburetor’s idle bypass valve also eliminates the need for holes in the throttle plates. This improves idle adjustments while keeping the correct throttle plate-to-transfer slot compatibility, and helps to maintain good idle control when using radical camshafts.

The Ultra XP design proved helpful to Duell, who will be competing at the rest of the NMCA events scheduled this year, as well as the Monster Mopar Weekend set for the end of August. With the current success he's been having with his Holley Ultra XP equipped Plymouth, it's likely he'll have enough points to take home the 2013 NMCA Nostalgia Super Stock Championship this year.
By Candace Wittrock, DS Media