Jeff Scuffins had a plan going into the Marine Corps Marathon yesterday, but it didn't include a runaway victory to shatter the course record by a startling 2 1/2 minutes.

Then again, how could he have known? He'd never run a marathon before.

Scuffins, 25, who works in the credit department for Citicorp Bank in Hagerstown when he isn't training, made an appropriate champion for this so-called "people's race," in which 60 percent of entrants were first-time marathoners.

He arrived here with one goal -- to qualify for the Olympic trials next spring by finishing in under 2 hours 20 minutes. With a little help from a friend, he wound up breezing in far ahead of the pack and almost six minutes ahead of his projected time.

He and his training partner and best friend, Chris Fox, broke away from the front-runners about eight miles into the 26-mile 385-yard course. Though later denying collusion, they left little doubt they were working together. Speeding through Georgetown at a 5-minute-a-mile pace, Scuffins took a cup of water from an onlooker, drank half and handed the rest to Fox.

But two miles later Scuffins was on his own as Fox slapped his partner's hand and stepped off the roadway, his day as impromptu pacesetter complete.

Scuffins never again had a serious rival from among the 12,089 entrants in the largest Marine Corps Marathon field ever. He lengthened his lead over the next five miles, and when he finished in 2:14:01 was more than five minutes ahead of Darrell General of Temple Hills, Md., whose 2:19:08 made him the only other man in the field to qualify for the Olympic trials. Scuffins' performance easily broke the previous men's record of 2:16:31, set by Dean Matthews in 1981.

The women's winner of the nation's third-largest marathon was Mary Robertson of Richmond. She slipped past Mary Salamone of Centreville, Va., who had led women entrants all day, at mile 24 and won in 2:44:36, well off the women's course record of 2:41:48 set in 1980 by Jan Yerkes.

Robertson, Salamone, third-place Elizabeth Andrews of Norfolk and fourth-place Sally Strauss of the District all qualified for Olympic trials with times under 2:50.

It was, by most competitors' accounts, a fine day for a marathon, with temperatures in the 50s, a light overcast and a gentle breeze blowing off the Potomac.

Nonetheless, medical personnel treated 581 runners, mostly for minor dehydration or exhaustion, and 13 later were hospitalized. There were no serious mishaps, though, and nothing to compare to last year's tragedy when a runner died. The marathon medical director, Lt. Col. Peter Mendel, said slightly higher temperatures this year probably accounted for the increase in treatments.

Generally, runners seemed delighted with the weather. "Conditions were perfect," said women's winner Robertson, 25, an attorney. "People kept saying, 'Are you hot?' But I felt cool all day."

She said her primary goal, like Scuffins', was to qualify for the Olympic trials. To that end, she kept to a rigid pace of 6 minutes 15 seconds a mile early on and didn't think about overtaking Salamone until about mile 20, when she started closing the gap.

"I knew I was about two minutes behind her," said Robertson. "But then my friends on the sidelines were saying, '1:10' and then '56.' When I heard I was 36 seconds back at mile 22, I knew I could catch her."

When Robertson forged into the lead at mile 24 she told Salamone, "Good work." Salamone, in her first marathon, said she tried to shout back, "Go for it," but didn't have the energy left.

Scuffins, meanwhile, battled foot blisters that left him bloody and limping after the finish. But he impressed onlookers by setting a lightning pace and never wilting.

Fox said the game plan was for Scuffins to stay with last year's winner Brad Ingram in the early going. But Ingram faded quickly and Scuffins and Fox found themselves side by side, moving easily into the lead. Fox, a specialist in shorter distances, said he never intended to go beyond mile 15, and when his feet blistered at mile 11 he wished his longtime running partner well and stepped off the track.

Scuffins was suffering with blisters, too, Fox said, "but he told me, 'I made a commitment. We're out here in the lead. I've got to keep going. I just hope my feet hold out.' "

He not only continued, he picked up the pace, running several 5-minute miles between the 11- and 20-mile marks. "Those 5-minute miles gave me a cushion," he said later. Suddenly, said his coach, Greg Shank, "We realized our 30-second lead was 90 seconds and we could win this thing."

But Scuffins paid a price. He strained in pain the last three miles, and when he crossed the line he limped immediately to the medical tent. His feet were drenched in blood.

Later, he hobbled out in a pair of bloody socks and said bravely: "It looks worse than it is."

Officials estimated that 12,000-15,000 spectators crowded the start-finish area near the Iwo Jima memorial, and thousands more lined the course as it wound across the Potomac, through Georgetown, around Hains Point and back to Virginia.

First to finish overall was wheelchair winner Ken Archer of Bowie, who won the event for the seventh time in nine tries in a time of 2:04:02. Hours later, the last of the runners were still struggling in as afternoon gave way to evening.

The latecomers tried, like Scuffins, to keep their minds on business. "Everybody was telling me, 'Record pace,' " said the winner, "but I was just trying to stay focused. It's a long way. You just have to take it one mile at a time."

Chuck Moeser of Thornton, N.H., profiled in Friday's Washington Post marathon preview, finished seventh, running 2:26:32. It was two minutes slower then his best, run five years ago. He was predicting a time of 2:18 and a win.

Although all the wheelchair results were unavailable, Billy Demby, the amputee who plays basketball in the Dupont Co. commercial, finished sixth in 2:32, smack in the middle of the 12 wheelchair entries. The time is six minutes better than last year when he was forced to stop and change a flat tire at 20 miles.

Tjela, Trujillo Win

United Press International

COLUMBUS, Ohio, Nov. 8 Ernest Tjela of Lesotho won the Columbus Marathon in 2:11:40 today. Maria Trujillo of Mexico shaved more than a minute off the course record for women, finishing in 2:32.08.

Organizers estimated that 4,000 runners participated before about 200,000 spectators.