Which parts are interchangeable between 1980 and 1981 Mazda RX-7 FBs?

The 1980 (SA chassis) and 1981 (FB chassis) Mazda RX-7s share a lot of DNA, but 1981 marked a significant mid-cycle refresh. While many major mechanical parts are a direct swap, Mazda made several design and electrical changes that prevent a 1:1 interchange across the board.

Here is the breakdown of what interchanges between the 1980 and 1981 model years:

Drivetrain & Engine

• Engine: The non-turbo 12A engines are mechanically interchangeable between these years ².
• Transmission: The transmissions will bolt up to the engine, but in 1981, Mazda shortened the transmission and moved the shift lever 30mm rearward ¹. Because of this, the center consoles do not swap between the two years ⁵.
• Cooling: Radiators and front-mount oil coolers are fully interchangeable ⁵.
• Fuel System: Fuel pumps are identical, but the fuel tanks do not interchange due to different shapes and mounting points ⁵. The 1981 tank was also increased to 16.6 gallons ¹.

Suspension & Brakes

• Suspension: Front and rear suspension components (springs, shocks, and control arms) are a direct swap ⁵.
• Rear Axle & Brakes: The rear axles are physically compatible, but if you are swapping a 1981+ disc brake rear end into a 1980, you will need an adapter brake hose. Mazda changed the brake line thread pitch starting in 1981 ⁴.
• Wheels: Despite some confusion out there about the 1981 chassis update, all 12A-powered RX-7s use the same 4x110 wheel bolt pattern ³.

Body & Interior

• Direct Swaps: The doors, hood, nose panel between the headlights, headlight covers, wiper grilles, and sunroof panels are direct interchanges ¹². Wiper racks and motors also swap cleanly ⁸.
• Fenders & Bumpers: Front and rear fenders are similar but not directly interchangeable without modifying the bumper fitment. The 1980 SA uses separate bumpers, while the 1981 FB uses integrated bumpers ¹² and ⁶.
• Interior: Seats, dash, and headliners will swap over. However, the 1981 interior was heavily redesigned—the instrument cluster, radio surround, heater controls, and door panels are different ¹.

Electrical & Ignition

• Ignition System: The 1980 uses a one-year-only ignition setup with a separate igniter box on the strut tower. In 1981, Mazda moved to a fully electronic distributor with the igniters mounted directly on the distributor body. You can swap the 1981 distributor and wiring into a 1980, which is a highly recommended upgrade for reliability ⁵ and ¹. Ignition coils themselves are identical between the years.
• Starting & Charging: Manual transmission starters are interchangeable from 1979 through 1985 ⁸. The alternators will bolt up, but be aware that the 1980 uses an external voltage regulator, while the 1981 is internally regulated ⁶.