Jack Kvancz is back in Division I--and doesn't have to move away to get there.

George Mason University filled its athletic director vacancy yesterday with Kvancz, Catholic U.'s hard-driving basketball coach/a.d. who kept his and his team's heads up despite CU's deemphasis to NCAA Division III, a bitter pill for him.

Of GMU, Kvancz told The Post last night, "I'd grown so fond of the place because I live out there (in Fairfax) and had spent so much time there. My son, Scott, had been making me go to every game. Before you know it I had been saying, 'Hey, this is a pretty good school.' The only hitch was giving up coaching, which I'll miss."

But he'll be behind Coach Joe Harrington all the way: "Our big push (at Mason) will be on basketball. That's what we've got to run with. That's where we're going. Some things may have to be dropped. But we will push basketball."

During June, Kvancz--already briefed extensively by GMU's assistant a.d., Jay Marsh--will work half days at both CU and GMU . . .

July 15 is the new date for the Marvin Hagler-Thomas Hearns middleweight title mix. Promoter Bob Arum says an antsy Hagler reluctantly agreed to wait that long, although Hearns' hand should be healed well before then, because there is a problem of TV satellite availability . . .

Lotte Mwale has "persistent double vision and severe bruises" to his right eye, an Atlantic City specialist declared yesterday, so add one to the rash of injury-induced title bout postponements. Mwale's challenge Saturday of WBC light heavy champ Dwight Braxton off indefinitely . . . But WBA lightweight ex-champ Hilmer Kenty, whose ring career was thought ended by an eye injury (probably more severe than Ray Leonard's) a year ago, comes back to fight Chris Fernandez June 11 in Detroit . . .

"The People's Cherce" of the 1940s Brooklyn Dodgers, Fred (Dixie) Walker, who died yesterday (Page B10): What an outfield the 1941 pennant-winning Bums had with Hall of Famer Ducky Medwick (.318 that year; died 1975), Pete Reiser (.343; died last fall) and Walker (.311)!

American U.'s golf team, 22-2 this season, has made it to the NCAA championships in Pinehurst, N.C., one of 25 schools invited. Go get 'em, Regan O'Rourke, Wade Heintzelman, Greg Carpousis, Ian Noel and Scott Jefferey . . .

Now, GU's Dr. John Thompson. At Wheeling College commencement Saturday, Thompson became honorary doctor of humanities--conferred by WC's president, Rev. Charles L. Currie, S.J., ex-GU chemistry professor and member of the coach search committee that found Thompson.