Ray Floyd made a tap-in birdie on the final hole to move into a three-way tie for the lead with Mike Reid and Bob Tway yesterday after the third round of the PGA Tour's $600,000 Hanover Westchester Classic in Harrison, N.Y.

Floyd, going for the 20th victory of his 24-year professional career, struggled through wind and rain to a round of 70, 1 under par on the Westchester Country Club course. He, Reid and Tway were at 205, 8 under par.

Tway, a winner in San Diego earlier this year, had a 69 in the rain. Reid, closing in on $1 million in career earnings but not yet a winner in 10 years on the tour, birdied the 18th hole to finish at 68.

Willie Wood salvaged a 73 and was two shots off the pace.

Brett Upper, Gil Morgan and Scott Simpson were another stroke back at 208.

Tom Watson shot a 70 and was seven shots back at 212. Also at that figure, 1 under par, was former Westchester champion Andy North, who will defend his U.S. Open title next week on Long Island. North had a 72 . . .

Juli Inkster shot a 3-under-par 69 to increase her lead to eight shots after the third round of the $450,000 LPGA McDonald's Championship at White Manor Country Club in Malvern, Pa.

Inkster, who had a five-stroke lead after two rounds, had three birdies and no bogeys as her 12-under-par 204 allowed her to keep the lead she has held since the first day. She also tied the tournament record for 54 holes, set by defending champion Alice Miller last year.

Mary Beth Zimmerman is in second place at 212 after a 1-over-par 73.

Ten shots back, at 2-under 214, were Ok-Hee Ku, Val Skinner and Judy Dickinson.

Kathy Baker made the only hole-in-one of the tournament yesterday, putting in a 4-iron on the par-3, 162-yard 17th hole . . .

In Dallas, Don January sank a 30-foot birdie putt on the 18th green to break a tie with Chi Chi Rodriguez and take a one-stroke lead in the Senior Players ReUnion Pro-Am at soggy Bent Tree Country Club.

January, who hasn't won a tournament in his hometown in 30 years, hit 17 greens in regulation as he shot 4-under-par 68 for a 10-under-par 134.

Rodriguez, who was tied with January before this round, shot a 3-under 69 for 135. The winner will earn $26,000 in this 54-hole tournament . . .

Severiano Ballesteros shot a third-round 70 for an 11-under-par 205 to take a two-stroke lead in the $300,000 British Masters tournament in Woburn.

Britain's Robert Lee is second at 207, with West German Bernhard Langer and American Rick Hartmann tied for third place, another stroke behind.

Ballesteros has led European tournaments three times this season with one round to play, but has yet to win this year.

He said, "It's better, though, to have led three times and lost than never to have led at all. If I could win here, it would do a lot for my confidence -- and I need a little bit of that right now." . . .

Briton David Curry won the British Amateur at Lytham St. Annes by the biggest margin since 1934.

Curry, 22, beat fellow Briton Geoff Birtwell, 11 and 9, in the 36-hole final. Curry will compete in next month's British Open and next year's U.S. Masters.

AUTO RACING

Al Unser Jr. won the Budweiser International Race of Champions at the Mid-Ohio Sports Car Course, a 2.4-mile, 15-turn road course in Mansfield, Ohio.

Unser toured the 29 laps in 49 minutes 53 seconds, 2.9 seconds ahead of Indy 500 winner Bobby Rahal, who had to settle for second place on his home track. Unser, 22, became the youngest driver ever to win an IROC race . . .

In Long Pond, Pa., Geoff Bodine smashed the Pocono International Raceway stock car qualifying record, turning a lap of 153.652 mph in winning the pole for today's Miller High Life 500 in a Chevrolet Monte Carlo SS. Bodine was one of seven drivers to break the mark of 152.563 mph, set last June by Bill Elliott . . .

Eddie Johnson of Ashland, Va. won both races in the Miller Trustworthy Twin Fifties at Old Dominion Raceway in Manassas. He was driving a Ford Mustang.

In the first race, second place went to Danny Fair of Hoadley, Va., who was driving a Firebird. Doug Hartley of Owings, Md., driving a Firebird, finished in second place behind Johnson in the second race.

BASEBALL

Two George Washington players were selected Monday by the San Francisco Giants in the major leagues' annual amateur draft. Pitcher/outfielder Gregg Ritchie was chosen in the eighth round and second baseman Kevin Fitzgerald was selected in the 23rd round. The two will report to the Giants' Class A Northwest League team in Everett, Wash.

ROWING

Brown caught favorite Pennsylvania at the three-quarter mark and raced past the Quakers to claim the 1986 Intercollegiate Rowing Association Challenge Cup at Onondaga Lake in Liverpool, N.Y. It was Brown's second Challenge Cup win in four years and third in the regatta's 84-year history.

The Bruins finished the 2,000-meter sprint in 5:50.2, about a half-length in front of the Quakers' shell. The Bruins' record-setting performance overshadowed outstanding pulls by Navy and Pennsylvania, both of which turned in sub-six minute times.

Brown finished second in overall points during the three-day regatta. The Bruins finished with 317.9 points. Navy was third with 266.7.