Top sprinters from all sections of the country will gather at Pimlico Saturday for the first running of the Frank J. De Francis Memorial Dash. On paper, they all look very fast.

But as handicappers try to sort out their relative merits, they should recognize that, in American racing, there are two types of speed. There is California speed, and there is everybody else's version of speed.

Even though the champion filly Safely Kept comes into the $350,000 event with 13 victories in her last 14 starts, she has amassed that impressive record by beating Eastern sprinters.

The one time she hooked up head-and-head with a California speedball was her one loss in the last two years. At Pimlico, she will be meeting another invader from the West, the brilliantly fast Sunny Blossom.

This assessment of the relative merits of horses on the two coasts has nothing to do with regional prejudice. It is an inescapable fact. Perhaps the best demonstration of eastern speed vs. western speed was the performance of Groovy in the 1987 Breeders' Cup Sprint.

Groovy was the best sprinter to compete in New York in the last decade. He dominated his opposition consistently, and his winning times were nothing short of sensational.

In my system of speed figures, he earned the kind of numbers that Secretariat did. He was hailed as a horse- of-the-year candidate before the Breeders' Cup. Yet he wasn't even fast enough to get the early lead in the Sprint. Two California females outran him for the early lead, and one of them, Very Subtle, trounced him by four lengths.

A more recent and equally vivid example of East Coast speed vs. West Coast speed came in the A Phenomenon Stakes at Saratoga Aug. 4. Mr. Nickerson was the reigning sprinter in New York, having led all the way to win four significant stakes there this spring.

He appeared clearly superior to a California invader, Prospectors Gamble, who had not gained the early lead in any of his sprint races. Yet Prospectors Gamble dashed to the front and led all the way.

California horses are quicker. But why?

Eddie Gregson, who trains Sunny Blossom, believes the reason is the different nature of the racing strips in the West. "My feeling," he said, "is that training on glib tracks teaches horses how to be faster. They develop speed skills better than horses training on cuppy tracks."

Moreover, Gregson said, "There is a difference in the basic style of training in the West because of the ground we train over. In the East, trainers like to get their horses fit with long gallops. One year a trainer from the East came out here and gave his horses all those two-mile gallops, and by the end of the season they were all limping off the track.

"Those long gallops {over a hard track} take too much of a toll, so in order to get a horse fit you have to work them faster."

For this reason, it is common to see good horses in the West working five-eighths of a mile in 58 seconds every five or six days -- a type of regimen unheard-of in the East. Horses' speed is honed in training and used to the fullest in actual racing.

Because of the speed-favoring nature of the hard California tracks, jockeys try to put their horses on or near the lead whenever they can. They come out of the gate in an all-out drive. And so horses get accustomed to running fast early fractions that seem almost unimaginable to easterners.

In one race at Santa Anita last year, Sunny Blossom ran a first quarter in 21 flat and a half mile in 43 3/5. Last winter, at the same track, he reeled off fractions of 21 2/5 and 43 2/5 en route to a record six-furlong time of 1:07 2/5.

The gelding made his first trip to the East Coast in March, where he faced a field of speedballs, including Once Wild, who had had the early lead in every one of his career starts except one in which he was wiped out at the start. Sunny Blossom left them all for dead, opening a lead of more than three lengths after a quarter mile.

This is the challenge that Safely Kept must face Saturday. The Maryland-bred filly is brilliantly fast, but for the most part she has been cruising effortlessly to the lead against slower horses. The only time she has faced a rival with comparable speed was in the Breeders' Cup Sprint, in which she hooked up with the fleet California-based Olympic Prospect.

Safely Kept won the battle, outdueling Olympic Prospect, but she lost the war. Her early exertions took such a toll on her that Dancing Spree rallied to catch her in the final yards.

Sunny Blossom is as quick as Olympic Prospect was, and he will give Safely Kept her toughest test since the Breeders' Cup. If the filly is good enough to cope with California-type speed and still win, she is a champion indeed.