Republican presidential hopeful Rep. Philip M. Crane said yesterday that if he were president, he would have given the Soviet Union a 48-hour ultimatum to get its military brigade out of Cuba.

If the Soviets refused, Crane said he would have "jerked the SALT II treaty from under them" and ordered a "Kennedy-type blockade" around Cuba.

"If you're going to draw the line," the Illinois Republican added, "what better place to do it than 90 miles from our own shores?"

Crane, speaking before a breakfast meeting of reporters, said he believes the Soviets would have withdrawn their Cuba-based troops if the United States threatened to pull out of SALT negotiations. But, he said, he would not hesitate to put a naval blockade around Cuba, as President Kennedy did during the Cuban missile crisis of 1962, and levy economic sanctions against the Russians.

The statements were among the most strident that Crane, an ultra conservative whose longshot bid for the GOP nomination has appeared stalled in recent months, has made on foreign policy issues.

He flippantly dismissed reports that the troops had been building up gradually for more than a decade, saying "I can't believe they've been there for 10 years hiding in a cave."

On domestic issues, Crane said he would welcome a presidential candidacy by Sen. Edward M. Kennedy (D-Mass.) because it would provide a forum for "the long overdue debate over the differences between the Republican and Democratic parties."

"He [kennedy] is the last unblemished liberal in Congress," Crane said, "Everyone else is running for cover."

As a potential Kennedy opponent, Crane said he would not mention the Chappaquiddick incident, in which a young woman riding in a car with Kennedy drowned. Then he promptly began talking about various articles he had read on the incident.

"At least no one died in Watergate," Crane said, quoting from one article.