HD Semi-Solid Engine / Transmission Mount Set. Porsche 911 / 912 1965-89

Enhance drivetrain precision and performance with the HD Semi-Solid Engine / Transmission Mount Set, designed specifically for Porsche 911 and 912 models
These heavy-duty mounts replace the factory rubber units with a semi-solid, high-durometer compound — around 25 % firmer than standard — providing improved control and response without sacrificing comfort.
The semi-solid design effectively reduces engine and gearbox movement under acceleration, braking, and cornering, giving sharper throttle response, smoother gear changes, and tighter handling stability.
Sold As A Set.
x2 Sets Required Per Car.
Work As Engine Mounts In 1965-1989 911/912/930
Work As Transmission Mounts In 1972-1986 911/912/930 (915/930 Transmission Only)

• Porsche 911 1965-1968 2.0L / 912 SWB (F)
• Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 911 1975-1977 3.0L Turbo (930)
• Porsche 911 1978-1989 3.3L Turbo (930)

• In the Heavy Dusty semi-solid version, the stiffer rubber reduces unwanted flex while still providing some damping, hence a compromise between fully soft and fully rigid (solid) mounts.

• Engine / gearbox movement or “rocking” under throttle or deceleration
• Clunking or banging noises from the engine bay when shifting or applying torque
• Increased vibration in the cabin or floorboard
• Misalignment over time, causing stress or wear in driveshafts, couplings, or mount brackets
• Feel of looseness or lag in throttle response or drivetrain “lash”

• Sharper Response & Less Flex - Because mounts deflect less, the engine / gearbox stays more stable under load, improving throttle response, shift feel, and power delivery.
  
• Better Drivetrain Alignment - Less movement helps maintain correct angle relationships between engine, gearbox, driveshafts, etc., reducing stress and wear.
  
• Improved Stability Under Load - During hard cornering, braking, or acceleration, stiffer mounts help avoid drivetrain “twist” or slop, which can upset handling balance.
  
• Dampening Retained - Semi-solid design still absorbs vibration and noise more than fully rigid mounts, providing a balanced tradeoff for street use.
  
• Straightforward Installation - Because the inserts fit existing mount shells, installation is simpler — no need for custom brackets or drastic modifications.
  
• Good for Performance / Restoration Builds - Especially in cars that see spirited driving or occasional track use, the HD semi-solid mounts are a common upgrade that improves control without completely sacrificing comfort.