I think you have a few facts mixed up. Motor mounts have nothing to do with the torque arm.
I have solid motor mounts in my car and they are specific for third gens.
Moroso part numbers
Upper mount #62510
Lower mount #62610
The solid mounts just keep the engine from torquing over under hard accelleration. If the engine doesn't move then the energy that used to try to rotate the energy is transmitted down the driveline to where you can use it. The downside to solid mounts in a street car is that there is no isolation between the engine and the frame. This means vibrations will be felt in the car.
Since the torque arm deals with the rear suspension and not the engine, replacing the motor mounts will have no effect on the torque arm. You still need the torque arm unless you change the rear suspension to ladder bars or a 4-link.
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87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block
Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546
Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
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87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley
