1974
Gone was the single color enamel finish from '73. In '74 Mattel introduced 'tampo' printed designs on all castings. This was a multi-color paint stamping process that allowed for more intricate and exciting paint schemes on the cars. Mattel had experimented with tampo printing on cars since '69, but now it was bigger and bolder. With this new method of decorating cars, the Flying Colors era was born.
Interiors
1974 castings included the following interior colors: ivory, dark brown, and (predominately) black.
Exteriors
Cars in '74 generally came in one or two tampo printed color schemes, but the rare casting would come in three color schemes. The tampo design itself was the same, but the printed colors could be different depending on the color scheme and casting.
Wheels
In '74 open wheel hubs replaced the capped rear axle wheels from '73. All '74 castings came with open hub front and rear axles, though some early run cars can be found with rear capped wheels.
Casting Names and Part Numbers
This year Mattel started out by reusing existing part numbers and casting names. Maybe they had reduced staff with the slowdown in '73, but for whatever reason a dozen or so castings have the same number as previous years. This makes it confusing from a number perspective, but the two years are easily told apart by the tampo print design (or lack thereof).