Tied for the lead at the start of a day, Marucci and McCoy battled relentless winds up to 25 mph for a better-ball, 5-under-par 67 for a 197 total.
McCoy, an insurance exec from West Des Moines, provided most of the fireworks, canning a wedge for an eagle 2 on the second hole and adding two more birdies in the difficult conditions. Marucci, an auto dealer from suburban Philadelphia, birdied the final hole to hold off charging defending champs Steve Johnson of Chattanooga and Jeff Knox of Augusta. The latter pair had fallen four shots off the pace midway through the round, but closed the gap to just one going into the final hole.
Former Walker Cuppers Trip Kuehne and Danny Green are three back at 200.
In the Seniors division, Steve Earsley of Stuart . Fl., and Mike Rice of Houston are four shots in front of Russ Berkoben of Perrysburg Ohio, and Dan Smith of Naples, Fl., five ahead of defending senior champs William Boles and Marty West.