Monte Carlo SS: up-to-date performer

No, you're not on a race track but in the street version of a NASCAR racer, the Chevrolet Monte Carlo SS. The '84 version of Chevrolet's 2-door sports coupe, window-stickered at $10, 700, is a ''muscle car.'' No doubt about it. But it's a muscle car in modern dress.

It's certainly not the same power-packed sports car of the late 1960s and early '70s - before the Arab oil embargo of 1973-74, which knocked the auto industry off its feet - but a totally up-to-date kind of performance car.

Mechanically, the Monte Carlo SS is a computerized sophisticate.

It's a highly practical performer - more comfortable to ride in than the Corvette (at least to this motorist), and it does the job it was designed to do, with zest.

An adapted 5-liter engine with 4-barrel Rochester quadrajet carburetor turns out 20 percent more horsepower than the same-size stock 5-liter Monte Carlo V-8 - 180 at 4,800 r.p.m.

A low-back-pressure exhaust system emits a deep-throated growl, reminiscent of the muscle cars of yore. If you don't like the noise, you may not like the car.

The SS rides on an adapted version of the car division's F-41 sports suspension as well as Goodyear Eagle GT tires. The handling is pointed and direct; where you point it is where it goes. Keeping the car under control is not a ''drag.''

And speaking of drag, the aerodynamic kind is at least 25 percent lower than the early Monte Carlo SS models in 1970, yet the drag-coefficient reading of 0. 375 didn't do much for the gas consumption. With all that power, you can count on paying for it. The mileage was under 15 m.p.g. by rough estimate, with a 3 -speed automatic transmission. On the Interstate it would be better, of course.

(For 1985 the Monte Carlo SS gets a 4-speed overdrive automatic transmission, which should help the m.p.g. a bit.)

While the starting price of the Monte Carlo SS is $10,700, the test car carried a figure of $13,450, including all those power options that are nice to have but cost money to buy.