A wealthy Washingtonian once took Rabbi Herzel Kranz aside to tell him that with his energy and drive, he could be a millionaire.

"So I asked him: "What's the difference between me and you?" except maybe you can afford exotic trips," Kranz remembers. "The difference, I told him, is, "You who's made millions, what are you going to do? You need someone to come and twist your arm. And me - instead of being a rich man whose arm is getting twisted - I'm the guy who's come to twist your arm.""

Few people are more skilled at that art than Kranz, founder and chief arm-twister of the Silver Spring Jewish Center. For years he has prowled the suites of rich Washingtonians to raise money for his Orthodox Jewish center, Israel, Jews in the Soviet Union...the list runs on and on. When a Jew in Allenwood Prison eats kosher, for example, he can thank Kranz for pushing the rule through.

"I'm intense," admits Kranz, 48. "When I set myself on something I think is correct, I don't back off. You have to push, you live in a world where you have to push."

Once, when he was stalking a rich builder for a donation, Kranz couldn't get past the man's secretary. So he waited until his mark stepped on an elevator; the rabbi's foot held open the door while he made his pitch. It worked. "If they don't let you in the door," he says "I come in the window."

Kranz grew up in the hills of upstate New York, and at 16 he knew he wanted to attend a seminary. When he left 11 years later, his specialty was Jewish education. Even when he was teaching in several Washington synagogues, the hustler in him was trying to get out. At night he sold insurance, and he put together a discount coupon book for Carter Barron Amphitheater that area merchants sold. But he kept thinking about the 80,000 Jews in Montgomery County, 80 per cent of whom, Kranz says, were not affiliated with a synagogue. He saw a chance to make a market.

"I shook down the whole city," Kranz says of his years spent raising millions of dollars to build his Jewish center in Silver Spring;; "A banker told me I was doing everything backwards, that first you have to have a congregation, then you visit prominent people in the community and then you build. I did it the opposite."

In the early '70s - after some wheeling and dealing in real estate to put together the land necessary to house a school, synagogue, playground and administrative offices - Kranz realized his dream. The center's annual budget is now about $400,000 a year, and some 450 families make use of the day school, Hebrew school or synagogue. At any given time a felon or two might be helping maintain the place, part of Kranz's passionate program to rehabilitate jailed men. (When he got out of prison, one convicted con man slept for two years in a storeroom while he painted the exterior of the building.)

And after his daily morning services, Kranz gets about the business of trying to free a prisoner in jail, convincing senators to push harder for release of Jews in the USSR, springing a woman kept in a mental institution against her will, and a list of other projects that keep him working the phone like a bookie.

"The work is great; the time is short," says Kranz. "You lose one day, you've really lost two. The needs of your people are many, but their patience is short. You have to have something that shows intensity. It's persistence - who's going to go down to the wall to the end? In the end, it's God's will, but the human being has to do the maximum." CAPTION: Picture, no caption, By Douglas Chevalier