American power train offers A body 6 speed manual

6 gears,eh? I couldn't find a Mopar app.

With a double O/D, a 6 spd (4+2)is almost too much for a hot streeter.
This is because of the way the ratios play out, and how low the rpms fall in top gear;falling well below the cam's happy place.For most of us a 4+1 is more than adequate;especially if the ratios are progressively tighter as they approach Direct.
For a 4+2 to be effective,our cars would need to cruise at a pretty good clip, and for a pretty good distance, to make it worthwhile. With speed limits up here being 100kph(62mph) in most places, second o/d would put my rpm so low that the engine would be operating in a very inefficient zone. I suppose if first o/d was real tight, and strong enough, one could gear the car to trap in it. And then if second o/d was far enough away to put the sbm at around 2000@65 rpm with something like 4.30s,and 28s;now that would be something. Or, if the 6 was a 5+1, that would help our small blocks out a lot.

My car might not benefit with a 6 speed. I proved that with the GV behind the 3+1 A833. That combo gave me 5 useable, very tight, full-power ratios, plus 2 o/ds. The ratios were;
3.09(2.41)1.67(1.30)1.00(.78).55 and the splits were .78-.69-.78-.77-.78-.71 I ran this with 4.30s to be able to trap at 112@6000. Top gear was the equivalent of a 2.38 rear,making 65mph =1922rpm and the starter gear was 13.29.. That was pretty sweet. For a Strip/street car. But way too much shifting for a DD. I decided that for a DD,there really was such a thing as too many gears.
I currently run a 4+1GV, and am very happy. As a DD,with 3.55s,It has a starter gear of 10.97 and a highway gear of 2.77. This works very well with my 230/237@050/110 cam.
The ratios are 3.09-1.92-1.40-1.09-(.78od), and splits are .62-.73-.78-.71