American Muscle Cars v4.1 by DukeBoys
I don't know if is an official update from original authors or an evolution made by another community, but seems fine.
v3.0 have only Muscle Street cars, but on this v4.0 we find Drag, Dirt, Oval and GT (Trans-Am) versions of the cars, with different physics.
Test it and post your impression.
>>> American Muscle Cars v4.1 by DukeBoys <<<