When Evan (Big Cat) Williams slugs a golf ball, Binoculars are sometimes needed to see it land. Would you believe a high-powered telescope?

Chances are Big Cat can take the longest drive of your career and carry it, on the fly.

Williams, 30, golf's Sultan of Swat, will seek his third consecutive $15,000 first prize in the National Long Driving contest Aug. 2, prior to the PGA championship at Oakmont.

Williams' act has to be seen to be believed. The competition will be televised before the PGA final round Aug. 6 on WJAL TV-7, but to reaelly appreciate Williams' missiles, it is best to appear in person at the launch site.

Last year he won at Pebble Beach with an on-the-screws smash of 353 yards. On the 1976 PGA scene at Congressional he won with a 307-yard blast which split the middle of the spongy first fairway, into the wind.

"My cardinal fule is relaxation," said William from his home in Leonia, N.J. "If you can get rid of all the tension in your body, you muscles have a chance to work.

"I really didn't know I was that long compared to other hitters until I beat Jim Dent in 1974," said Williams, a good friend of former Maryland golfer Billy Ziobro, who recently took the head pro job at Beaver Brook in Clinton, N.J.

Evans grew up with the fifth hole at Englewood (N.J.) Country Club in sight from his back door. "I caddied there. We used to play as many holes as we could before the tractor man would kick us off."

His father, Tudor Williams, said his son could hit golf balls great distances by the time he was 12. "I never did buy clubs for him. He did everything himself. I always encouraged him to do what would make him happy."

For Big Cat, happiness is driving for show and dough. He earns a comfortable living giving exhibitions at $1,500 each. Last week he thrilled them in Ottawa and Philadephia.

Williams uses a graphite driver with an extra stiff shaft which, at 44 inches, is slightly longer than those used by the six PGA Tour players among his challengers - Dent, former Maryland star Billy Calfee, Lon Hinkle, Stan Altgelt, Ron Milanovich and George Cadle. Big Cat outhits Nicklaus with a two-iron.

Some of his more memorable shots have been a 397-yard blast in New Jersey that was measured with an odometer, and a clout that found the green on a 430-yard par-4 at Fort Lauderdale.

Williams' 6-foot-6, 210-pound frame enables him to create a large swing arc. He has a long, smooth takeaway and when he enters the hitting area he releases with a strong leg drive and delaued wrist break which creates blurring clubhead speed.

After watching one of Williams' smokers escape the boundaries of a driving range, former PGA champ turned announcer Dave Marr was quoted as marveling, "Most people don't go that far on a vacation."

Tony DeLuca of Chantilly and Oakton High will be bound for the University of Florida this autumn, seeking a golf scholarship.

Gator Coach Buster Bishop, who coached tour players Andy Bean, Andy North, Steve Melnyk and Bob Murphy, believes in making prospects earn their scholarships, so in early October, after qualifying tests, the top four Florida players will earn full scholarships and the second four will earn 50 percent coverage.

DeLuca, 18, winner of the Quantice Invitational and Virginia State AAA titles and the Northern Virginia Amateur, had feelers from North Carolina, Miami, Houston, Wake Forest, LSU and Southern Cal. He feels his chances of making the PGA tour will be best served at Gainesville.

Heroes Inc. raised $70,000 in its annual golf tournament last week at Indian Spring. Don Sheads, John Fentress and Don Stewart were the winner in the two-day outing that raised money for families of policemen killed in the line of duty.