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Automotive Mileposts  
Production Numbers
Thunderbird script
63A - Hardtop 35,758 ($3,630)
76A - Convertible 2,134* ($3,914)
1958 Ford Thunderbird Hardtop in Raven Black
1958 Thunderbird Hardtop shown in Raven Black
INTRODUCTION DATE February 13, 1958
Production Started December 20, 1957
Production Ended September 16, 1958
*Production of the 1958 Convertible models was delayed due to various reasons, and the Convertible wasn't officially introduced to the public until June, 1958. This, in part, accounts for the very low production numbers of the 1958 Convertibles.

Despite its late introduction date, and the fact that 1958 was not a good year for automobile manufacturers, the Thunderbird was one of only 2 automobiles to show a production and sales increase for the year. Although the introduction of a four seat Thunderbird was widely panned by many, the fact remains that this was a prudent decision by Ford, and the beginning of a new era: the personal luxury car.

1958 Thunderbird unitized body construction
Above: unitized body construction was new for the 1958 Thunderbirds.

The Wixom Thunderbirds

On December 20, 1957 the first four passenger Thunderbird rolled off the assembly line at the brand new Lincoln Assembly Plant in Wixom, Michigan. Wixom, located about 25 miles northwest of Dearborn, was a state of the art facility. Covering a total area of 325 acres, the plant had 35 acres under one roof with 1,374,000 square feet of floor space. The cost to build this facility was huge, and to maintain a high level of quality control, only the Lincoln and Thunderbird automobiles would be built there. The Lincoln and the Thunderbird were the ideal platforms to share this space: both would be completely new for 1958, and both would be of single unit body "unibody" construction. Unibody construction differed from conventional body on frame construction in that the body and frame were one solid unit. Conventional automotive body construction mounts the body to the frame at critical points, and unibody construction was said to provide greater rigidity, reducing body twisting and flexing on rough roads.

Unibody construction was not new. The 1922 Lancia was the first car built this way. American auto makers were a little slower to utilize this construction, with the first American car, the Chrysler Airflow, introducing it in 1934. The Airflow was ahead of its time and was not a sales success. The 1936 Lincoln-Zephyr was more popular, and was followed by Nash in 1941, Hudson in 1948, and Chrysler in 1960. Other than strength, unibody construction also provides savings to manufacturers in weight and materials. Based on the same principal as aircraft construction, stresses are more evenly distributed throughout the structure. Unibody construction is best utilized in smaller platforms. As the size of the car grows, so do the problems with this type of construction. Rattles are normally reduced, but as the wheelbase is lengthened, road noises tend to be absorbed and distributed to a much greater degree than on conventional bodies. It can become very expensive in terms of weight and cost to isolate these road noises from the interior of the car. By 1963, Ford would be using over 140 pounds of insulation per Thunderbird to maintain interior peace and quiet.

The 1958 Thunderbird was one of a very few Ford automobiles to be designed from the outside in. Normally the basic engineering of the car (drive train, suspension, etc.,) is completed first. Then the stylists have to make their designs work within the parameters of the engineering platform. Not so on the 1958 Thunderbird. Initially just a styling exercise that began in March 1955, the concept had been accepted before engineering was even involved. This time, it was the engineering department that would have to answer to the stylists.

This created what is arguably the most significant automotive design of the fifties. Standing just 52.5 inches high, which was about 9 inches less than typical American cars of the day, the Thunderbird was one of the lowest American cars ever, with ground clearance a mere 5.8 inches! This fact contributed to a few problems for the stylists as well. The tunnel running down the center of the car was quite high, to accommodate the transmission and drive shaft. This contributed significantly to the Thunderbirds strength, but created an interior packaging challenge. It was decided to place a full length panel console down the center of the car, cover it with a color-keyed textured vinyl process that was relatively new, and utilize it to house ash trays, the radio speaker, heater and air conditioning controls, as well as power window switches. Initially other items were considered for this area, but were not included due to the possibility of moisture or dirt entering the components and creating problems.

Money was of course a concern, and with the styling department already using a good portion of the budget, the engineering department was forced to make more than a few concessions. As a matter of fact, underneath the stylish body and swank new interior, the 1958 T-Bird was about as conventional as they came. Originally intended to accommodate Ford Aire Suspension, possibly as standard equipment, the new Bird was equipped with coil springs all around. The large towers needed to accommodate the air domes for the air system had been finalized as part of the design before the decision was made to cancel the air suspension system. It seems that a few early Ford models equipped with Ford Aire were creating customer service issues for dealers. Reports of Ford owners waiting in excess of 15 minutes with the car idling to "air up" the domes after overnight periods prompted Ford to cancel the option. This left the Thunderbird with unequal length A-arms with coil springs up front, and trailing link type coil springs in the rear with upper links on each side running almost parallel with the arms. Torque reacting links were added to eliminate wheel hop under acceleration, which they did. However, they CAUSED it on washboard surfaces. Handling characteristics were at times a bit sloppy due to the suspension design.  MacPherson-strut front suspension was considered at one point, but shelved due to cost considerations.

There were other problems engineering the 1958 Thunderbirds as well, but they seem minimal when compared to what was going on over at Lincoln with their new 1958 platform. At one point late in the design phase, the Thunderbird had to be split down the middle and widened to accommodate tire clearance, and the brakes had to be reduced in size by a full inch from 3.5 to 2.5 inches wide to allow the front wheels to turn properly. This left the Bird with just 175.32 square inches of lining space, which was not enough for the 3,708 pound car. The suspension and the brakes are generally regarded as the weak points in an otherwise excellent package.

The unitized body would serve the Thunderbird well, and would be used through the 1966 model year. After that, the Thunderbird would become even more closely tied in with Lincoln design and body on frame type construction would be used. The backbone of the 1958-1966 Thunderbird would be its unitized body, among the strongest ever built and considered one of the best by many. Rust is the main concern with this type of construction, as it is very expensive to repair once it starts. Reports of Thunderbirds of this era having rusted out frames are not uncommon, and special attention needs to be given these cars to prevent rust, or catch it early before it can remove the car from its flight pattern permanently.