JOLIET, Ill. -- NASCAR's decision to take 10 Nationwide Series engines to its research and development center in Concord, N.C., for evaluation isn't an unprecedented move, but it may be an indication of upcoming changes to rules governing engine packages in the series.

In its second year of competition, Toyota has dominated the Nationwide Series this season, winning 14 of 20 races. Of those victories, 13 have come from Joe Gibbs Racing -- five from Tony Stewart, four from Kyle Busch, three from Denny Hamlin and one from rookie Joey Logano.

Busch also has the other Toyota win, in the No. 32 Camry fielded by owner Todd Braun.

Toyota's dominance, particularly that of the nine-time winner No. 20 JGR Camry, has irritated drivers of other makes of cars, prompting series points leader Clint Bowyer, a Chevrolet driver, to assert that "a monkey could drive that 20 car and win."

Does Toyota have a horsepower advantage, as non-Toyota teams have claimed? The last set of dynamometer numbers, taken after Carl Edwards won in a Ford at Milwaukee, would support that assertion. A garage source told Sporting News that Edwards' peak horsepower was measured at 611, compared with 632 for the No. 20 Toyota, 628 for the No. 40 Dodge and 612 for the No. 88 Chevrolet.

After Friday night's Dollar General 300 at Chicagoland Speedway, which Busch won in the No. 18 JGR Camry, Bowyer's crew chief, Dan Deeringhoff, told Scenedaily.com's Bob Pockrass, "The peak number is maybe 20 [horsepower difference], but I think the average is quite a bit more than what we've got."

NASCAR took engines from the No. 18 and No. 20 Gibbs cars, in addition to the power plant from Braun's No. 10 Toyota, which Brian Vickers drove to a fourth-place finish Friday night. Chevrolet engines that will be measured are from the No. 88 of JR Motorsports, driven by third-place finisher Brad Keselowski; the No. 11 of CJM Motorsports, driven by Jason Keller; and the No. 2 of Richard Childress Racing, driven by Bowyer.

In addition, NASCAR took engines from the Nos. 16 and 17 Roush Fenway Racing Fords driven by Greg Biffle and Matt Kenseth, respectively, and from Dodges driven by Elliott Sadler (No. 9 of Gillett Evernham Motorsports) and Dario Franchitti (No. 40 of Chip Ganassi Racing).

NASCAR will decide whether or not to make rules changes after reviewing the numbers from the upcoming dynamometer tests.