General Motors seems determined to milk the F-body (Firebird and Camaro) for everything it can before the car goes out of production sometime after next year. That's why there is a 1991 Firebird convertible sitting in showroom of your local Pontiac dealer. With tooling costs paid for long ago, the car, even now when being built in lower volumes, is a terrific money-maker for GM. Chevroletdid the legwork a couple of years ago for making the Camaro into a convertible. Now Pontiac has come up with a version of the car by adding the appropriate trim. So, after an absence of more than 20years, the Firebird convertible has returned to the Pontiac lineup. In addition to a standard production model, you can open your wallet a bit wider and order a high-performance Trans Am convertible. The Trans Am convertible has macho written all over it. The car is loud and fast and loves to be driven hard. ENGINE, PERFORMANCE An ample amount of power comes from the 205 horsepower, 5.0-liter, fuel-injected V-8 installed in the Trans Am. Even though the car is fairly heavy at 3,442 pounds, it still performs with traditional Firebird muscle. When revved, the exhaust system howls and growls. Some extra pressure on the gas pedal ensures a powerful performance and, if you wish, a good amount of tire squealing. The car's four-speed automatic transmission shifts smoothly and allows the engine to settle into a relaxed cruising mode on the highway while turning over about 2,000 or so rpm. Even so, the Trans Am is no economy car. Driven with a tender foot, I came up with about15 miles per gallon in the city and 21 on the highway. However, the test vehicle was delivered with less than 100 miles on it; fuel mileage may increase slightly after break in. STEERING, HANDLING If you can accept a few compromises, the Firebird Trans Am convertible is great fun to drive. Though the car is much better in straight line situations, the Firebird does take a curve with verve -provided the driver learns how to safely manipulate the pedals. On slippery roads, the rear end is easily broken loose. The suspension on the Trans Am convertible is a bit soft, at least when tackling large dips in the road. I came close to finding the limit of the suspension system several times by traveling quickly over large bumps. It takes a day or so to learn the car's limits. The power disc/drum brakes do a decent job of slowing the car. One wonders, however, why four-wheel discs aren't standard on such a high performance machine. FIT, FINISH, CONTROLS I got caught in a rainstorm while driving to Daytona Beach. I pulled over and had the top up and locked into place in about one minute. Some might complain that a $25,000 car should have a power top. In this case, I disagree. The manual top is, with a little practice, very easy to use. In fact, the top usually can be raised and lowered manual ly more quickly. And with a power top, there are more mechanical parts that can break. As with the Camaro, the cloth top is neatly stowed under a flush-fitting fiberglass tonneau cover. Visibility with the top up is decent, though not great. The top has a fairly large rear window, meaning that there is a blind spot on either side. Except for Mercedes-Benz, no carmaker seems to be making convertible tops with three windows anymore. There is a cacophony of noises in the Firebird. Numerous squeaks and rattles come from the rear area, but that always has been a trait of the F-body cars. The convertible top is the cause of much wind noise, probably because the side of the top fits poorly when raised. Switchgear is all standard-issue GM stuff located in the usual positions. The cruise control and windshield wiper switch is located on the steering column. The gauges - big, round analog instruments - are very easy to read and nicely laid out across the dash. The seat are absolutely superb. Rear passengers may find the back seat a bit tight, though. There's no glove box in the Firebird. There is a leather pouch instead. But there is a big center console. A driver's side air bag is standard. Basically, the car is old and feels it. It's a product of the 1970s. Chopping off the Firebird's roof is another attempt by GM to buy time and squeeze more profit out of the car. Pontiac plans to build 2,000 Firebird convertibles in 1991, so the car may have some collector potential. Anyway, a new Firebird with '90s technology is due out in 1993.