The two-day better-ball event at the par-71 Rhode Island Country Club concludes on Tuesday.
Calcavecchia made eight birdies for his team, including a 50-footer at the par-three 10th. Price nearly aced the par-three sixth, as his tee shot finished within six inches of the hole.
DiMarco and Hart, teammates at the University of Florida, matched the top score with a 60.
Jeff Sluman and Stuart Appleby are three shots back at eight-under, along with Brett Quigley and his uncle, senior player Dana.
David Duval and Peter Jacobsen are four shots off the pace, while the teams of Craig Stadler and Steve Elkington, David Toms and Stewart Cink and Billy Andrade and Brad Faxon are five behind. Andrade and Faxon are the tournament hosts.
The 10-team field is rounded out by Justin Leonard and Rocco Mediate and Len Mattiace and Shigeki Maruyama, each of whom carded four-under 67s.
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