The fourth generation was an expansion on that start.Unlike the third-generation "Bullet Birds" how brought style to the four-seat Thunderbird, the forth was more an evolution of style than a whole new invention.
The Thunderbird was restyled in favor of a more squared-off, "formal" look for 1964 . The Thunderbird’s sporty image had by that time become only an image. The standard 390 cu. in. 315 bhp engine needed nearly 11 seconds to push the heavy T-bird to 60 mph (96 km/h), although with enough room a top speed of about 120 mph (200 km/h) was obtainable. The softly sprung suspension allowed considerable body lean, wallow, and float except on smoothly surfaced highways; there was an export suspension package available as special order. Contemporary testers felt that the Buick Riviera and Pontiac Grand Prix were substantially more roadable cars, but the Thunderbird remained the leader of the market segment.
Where the Bullet Birds were rounded, the next-generation "Jet Birds" (or "Sculpted Birds") were squared off and sharp. The proportions, however, were similar in silhouette with both a long hood and a long trunk over a relatively short 113.2-inch wheelbase. Dual headlights, a low-placed sweeping grille and upright windshield all were similar to the Bullet Bird, but the deeply sculptured sides were new as were the large rear taillights. In fact those taillights would become the new Thunderbird’s signature innovation — but not during ’64.
The revised ’bird was initially offered as a hardtop, a convertible, or Landau, with vinyl roof and simulated landau irons. The tonneau cover and wire wheels of the Sports Roadster remained available as a dealer-installed option, although only 50 were sold. Total 1964 sales were excellent: 92,465, up nearly 50% from the previous year.
Both coupe and convertible models continued with the 1964 Thunderbird and the separate Landau model also carried forward. However, the Sports Roadster was gone. Two versions of Ford’s 390-cubic-inch V8 were available both topped by Holley four-barrel carburetors. The base 390 used one Holley and a 10.0-to-1 compression ratio to make 300 hp while the optional high-performance version ran 10.5-to-1 compression and two Holleys and was rated at 330 hp. Both were backed by a three-speed automatic transmission.
"One additional item that should accompany milady when she drives her Thunderbird downtown for a shopping spree is an auto club membership," wrote Motor Trend. "Should a tire go flat, few women would be able to wrestle the heavy spare wheel and tire out of its high resting place or over the trunk’s high lip…Ford ’s Thunderbird fills its intended purpose. It’s a real prestige four-seater. Granted it’s not everyone’s cup of tea, but for bird lovers, it’s the ’only way to fly.’ Flight plans, anyone?"
Several features intended for the new generation were delayed until 1965, when front disc brakes became standard equipment and sequential turn signals were added. The latter feature flashed the individual segments of the broad, horizontal tail lights in sequences from inside to outside to indicate a turn. The delay resulted from legal difficulties with various U.S. state laws on vehicle lighting. Sales, impacted by increasing competition (including from Ford’s own Mustang), dipped to 74,972.
Sales were strong once again with Ford building 92,465 Thunderbirds during this model year.
The taillights became spectacular for 1965 as they gained sequential operation. Each taillight was divided into three segments which, when the turn signal was turned on, would light sequentially in the appropriate direction — quite a show. New reversed scoops appeared in each front fender and there were a few other trim tweaks, but the car was otherwise virtually unchanged from before. The drivetrains also carried forward though the front wheels now sat outboard of disc brakes. Despite the fascinating taillights, sales drooped to 74,972 Thunderbirds.
For 1966 the larger, 428 cu. in. (7.0 L) V-8 became optional, rated at 345 gross horsepower (257.4 kW) and providing a notable improvement in 0-60 acceleration (to about 9 seconds). A new Town Hardtop model was offered, featured a roof with blind quarter panels for a more ’formal’ look (at the cost of rear visibility). The Landau model was replaced by the Town Landau, which retained the previous model’s padded roof and landau S-bars, but applied them to the Town Hardtop’s formal roof. The Town Landau was by far the best-selling model, accounting for 35,105 of the 1966 model’s 69,176 sales.
Though the basic body shell remained intact, the 1966 Thunderbird was extensively restyled with a new, tight egg-crate pattern grille, and the two taillights were now connected into one massive piece of plastic. Generally speaking, it was the best-looking of fourth-generation T-Birds.
There was a very rare special order 427 available through certain ford dealers for 1963-1965 Thunderbirds, 120 of these ’high performance’ T-birds were made. Only 6 are still known to exist today. See the articles on the left of a 427 tbird, it is documented that Bob Tasca, a well known drag racer of the 60’s, ordered a factory fitted 427 1964 T-bird that was said to do 0-60 mph in 6 seconds flat with a top speed of 135 mph.
It was also — at least potentially — the quickest. While the base 390 V8 was now restricted by a two-barrel carburetor to 275 hp, a 315-hp version with a four-barrel was optional and a new 428-cubic-inch V8 with a four-barrel carb making 345 hp optional.
The ’66 T-Bird sold a so-so 69,176 units but was destined for fame. A quarter-century later, it was a ’66 Thunderbird convertible that Thelma and Louise drove off a cliff into oblivion in the film that wore their names as the title.
The next Thunderbird would take the car in an entirely new direction.