Going into the 1970s, it was hard to know exactly what direction cars like the Firebird were going to take. On the one hand, they could stay true to their roots, and risk extinction like so many others; on the other, they could turn into gutless economy cars like the Pinto-derived Mustang II. Thankfully, the Firebird was one of the few that could afford to stay the course, thanks largely to a bewildering array of option packages that helped it to become a car for everyone.
The Esprit trim was one step up from the base model on the Firebird food chain, one step below the Formula and two below the Trans-Am. With a few more trim and luxury items than the base model, the Esprit was effectively a Formula without the dual-scoop hood or dual exhaust, and without the four most powerful big-block engines available on the Formula. Engines on offer in this model included a 155-horsepower 350, and a 175-horsepower, 400 small-block Pontiac engine -- not to be confused with the Oldsmobile 403 that made it into Firebirds two years later.
The Esprit left the factory with 14-inch rims wrapped in E78-14 tires -- the closest thing available today would be either a 185/80R14, or a 205/70R14 if you want to step down a series. A 15-inch rim and F60-15 -- modern equivalent 225/70R15 or 235/60R15 -- were available on the Trans-Am. If you're looking for the biggest tires that will fit under your car, but want to stay with the original 15-inch look, you can squeeze 8-inch-wide wheels -- 4.5-inch backspace -- and 255/55R15 tires under the front, and 10-inch-wide wheels, with 5.125-inch backspace, and 285/55R15 meats in the rear wheel wells. A set of massive 315/30 tires will fit in the rear, provided you use 18-inch rims, 11 inches wide with 6 inches of backspacing.
