BALTIMORE, JULY 28 -- Chas'Whim, a burnished 3-year-old with a white sock and a knack for winning, ran fastest through the grass today to take the $67,675 Sir Ivor Stakes at Pimlico.

Chas'Whim was recognized as a dirt sprinter before the race, and as a well-rounded racehorse afterward. In his first attempt beyond seven furlongs and on turf, he fled eight others his age to win the Sir Ivor by six lengths over Life's Surprise.

With the death of Major Lux early last week, the Sir Ivor became a grab bag. Life's Surprise was the 9-5 favorite off two good turf races at Belmont Park, but Stage Colony (5 to 2) came in the only stakes winner. He was within five lengths of Chas'Whim well into the race, but couldn't mount a serious charge, finishing 8 1/2 lengths back in third.

Chas'Whim has caused Rodger Gill at least one restless night, but the veteran trainer promised to sleep well tonight knowing he has a truly versatile 3-year-old. Chas'Whim won his third straight race by rushing to the lead from the far outside and setting an honest pace for jockey Allen Stacy.

Although Chas'Whim went a half-mile in 46 4/5, Stacy said: "He had his ears pricked . . . and he hadn't begun to run. I had to keep tapping him on the shoulder" to keep his attention.

Turning into the stretch, Chas'Whim opened a two-length lead on Life's Surprise, who didn't lose any more ground until he began coursing about well into the lane. Richard Migliore was fighting him some as Chas'Whim pulled away, finishing the firm 1 1/16 miles in 1:41. The chestnut gelding, from Chas Conerly's first crop, paid $12.80 with his fifth victory in eight tries.

Chas'Whim's first victory was in a $50,000 claimer, and Gill said he couldn't sleep the night before for fear someone would claim him. Owned and bred by Harriet Heubeck of Hobeau Farm, Chas'Whim has become Gill's best horse and now provides the trainer a wealth of alternatives in gauging upcoming stakes races. Handicapper Leaves

Pimlico and Laurel handicapper Art Sinclair will leave the tracks Aug. 5 to take a front-office position with the Baltimore Blast of the Major Indoor Soccer League. Charlie Eckman and former Washington Post turf writer Clem Florio will handicap for the tracks until a permanent replacement is named.