You can still get them if you hurry -- hand-sewn suits for only $1,500

First Norman Block shows you the rich English fabrics. Next, he tells you that a suit must have ''balance'' - hang perfectly in any position - and that the pinstripes should match exactly on your lapels, pockets, and trousers. The texture, color, and style are chosen, then a paper pattern is cut to fit your figure.

If you've survived all this, all you have to pay is $1,500 a suit from now on.

That's right, $1,500.

And you'd better not wait too long at that. Mr. Block, chairman of Dunhill Taylors, tucked between Tiffany & Co. and a string of pizza parlors on East 57th Street, says the time is fast-approaching when custom, hand-sewn suits will cost

In fact, he's worried much more about finding tailors who can half-stitch, bind, and fine-draw than he is about finding customers.

''These tailors are going to be extinct eventually,'' says the diminutive, jolly Mr. Block, who has spent 59 years in the business started by his father.''There are very few hand-tailors coming up. They all came from Italy and Russia. There are no Russians coming anymore. The Italians, their sons are not going into tailoring -- even in Italy.''

Worldwide there are no more than 15 hand-tailoring companies.

Block himself is not a tailor. ''I can't sew a stitch,'' he exclaims. Rather, he is a designer, drawing the patterns the tailors use in cutting and sewing the material to match.

Like other retail clothing stores across the country, Dunhill has a selection of ready-to-wear and made-to-order, machine-made clothes at somewhat lower prices. The ready-to-wear winter suits start at $450, and the made-to-order suits (with some hand-finishing) start at a mere $800. But it is really the custom, hand-sewn jackets and trousers that have lured princes and potentates, actors and politicians, socialites and social-climbers.

Dunhill tailored an entire wardrobe for the late Edward, Duke of Windsor. In the early 1950s, the late Rafael Trujillo, dictator of the Dominican Republican, bought $40,000 worth of Dunhill clothes on one visit. Recently, a Texas oil tycoon who had purchased 12 suits the month before bought another 12.

''Don't you think you might be ordering too many,'' Block told the Texan. The oil man replied: ''I'll write you a check for this whole store and you can wrap it up and send it to Texas.'' Block refused -- settling instead on the sale of 12 suits at $1,500 apiece.

''All the Rockefellers and all the Vanderbilts come here,'' Block notes, perusing the customer files. Each customer's file contains sample ''patches'' of the color and type of fabric used in previous suits.

When Lyndon B. Johnson was vice-president, he came into the store looking for a sports coat, Block says. Finding that the coat was a little tight, the fitter pulled out a jackknife to cut a seam. Immediately, two Secret Service agents grabbed him as Johnson turned around and saw the knife. ''Well, boys, it's about time I caught my plane,'' Johnson declared, and the three of them left without another word, according to Block.

There are plenty of New Yorkers and out-of-towners alike who wander, rather naively, into Dunhill Tailors shopping for a suit or sports jacket, little realizing what ''company'' they are keeping. They pinch the quality of fabric in a sleeve, gape at the cut of a jacket's lapels - conservatively narrow, if you please. No, they say, hand-made apparel really wasn't what they had in mind, and they disappear into the surging sea of people on posh East 57th Street.

They can't argue with Norman Block about his prices.

''I've always believed that one gets what they pay for - and pays for what they get.''