Defending series champion Scott Parker will try to become the fourth driver to win consecutive American Motorcyclist Association Grand National-Camel Pro Series events at Hagerstown (Md.) Speedway as the two-wheel circuit comes to Hagerstown's half-mile dirt oval Sunday.

After a sluggish start, Parker dominated last year's AMA schedule with 10 victories, including his only half-mile triumph of the year at Hagerstown. And the 29-year-old should be the strong favorite to match last season's success. All of the previous winners of AMA Pro Series events at Hagerstown have repeated the following year.

"I guess it's a matter of just pure luck," said track spokesman Frank Sagi, unable to find a better explanation for the double victories. "But, they tell me luck is when preparation meets opportunity."

Bart Markel won the inaugural event in 1964 and won again a year later. Randy Goss was victorious the next time the AMA came to Hagerstown in 1983-84. Steve Morehead claimed wins in 1987-88.

Parker, looking to become the fifth driver to win three consecutive Pro Series season titles, is second on the dirt track career win list with 33 and needs only seven to catch Jay Springsteen to tie for first.

Over 10,000 spectators and over 100 riders are expected to be on hand at Hagerstown. Morehead will attempt to regain the form he showed on Hagerstown's dirt two years ago and Chris Carr will be trying to hold off Parker and extend his 1990 series points lead. Carr is coming off a victory at Peoria and leads Parker by 17 points (157-140).

Originally scheduled for July 14 but postponed because of rain, the racing afternoon will include seven 10-lap preliminaries and the 20-lap championship feature. In addition, the day's six fastest qualifiers will compete for a first-place prize of $10,000 in the Camel Challenge, a five-lap sprint. The gates open at 10 a.m. with practice beginning at noon, time trials at 2 and racing at 3.

Martin Leads, Barely

As the Winston Cup series heads into the second of nine straight racing weekends, this time in Brooklyn, Mich., Mark Martin has a 10-point lead over Dale Earnhardt. And with Richmond looming as the fifth race of the crucial stretch, Martin surely could use the points he lost at the Virginia track in February.

Martin won Richmond's February event but was penalized $40,000 and 46 valuable points after NASCAR officials found a prohibited spacer in his engine. His fifth-place finish at Watkins Glen last weekend helped give him his current advantage over Earnhardt, with 11 races remaining.

The Winston Cup returns to Richmond International Raceway for the Miller Genuine Draft 400 Sept. 9. Also on tap that weekend is the Autolite Paltinum 200, a Busch Grand National event to be staged Sept. 8 at 1:15. . . .

Al Unser Jr.'s win in the Michigan 500 two weeks ago ended a tense week with a win and a record. Al Unser Sr. crashed in practice, suffering a fractured right femur, a cracked clavicle and four broken ribs. Al Jr. then went out Sunday and ran the fastest 500-mile race in history. His average speed of 189.727 easily surpassed the previous record of 186.288 set by Winston Cup's Bill Elliott at the Talladega Speedway in May 1985.

Local Laps

If it's horsepower you're looking for, the Maryland International Raceway in Budds Creek will be the place to be for the Superchargers Showdown, Aug. 25. An all-pro field of dragsters and funny cars sporting 2,000-horsepowered supercharged engines will be featured. . . .

Rain has limited action at Old Dominion Speedway to 11 of the 17 scheduled events but the Manassas track hopes to make up the lost races with five straight racing weekends beginning with the Budweiser 100 Late Model feature Aug. 25.

Curtis Markham leads Old Dominion's Late Model division with four wins but trails Danny Fair in the points race. With two wins and consistent top finishes, Fair holds a 256-240 advantage. Frank Herbst (202 points) has a 22-point lead over Dan Lowery in the Grand Stocks and Ed Skelton leads Rusty Baltzell in the Hobby Stocks, 252-234, despite Baltzell's six wins. Mitchell Harris, with nine wins, leads the Mini Stocks.