The '67 has the torque arm(s) to eliminate harmonics and wheel hop that was caused by the non-staggered shocks. I read somewhere the base OHC-6 cars didn't get them. The Sprint got one, and so did the 326 on the passenger side. The HO 326 and 400 received them on both sides.

I don't think it mattered what type of transmission was in the drive line. It was the matter of HP the determined what the axle was equipped with.

The engineers figured out the problem before the '68 model year and staggered the shocks, eliminating the need for the torque arm(s).