I've probably had about a dozen 383s and a few 440s in '67-'70 B-bodies through the years.
Stock, some were definitely stronger than others.
A couple of the AT cars would definitely light 'em up from a dead stop - probably torque multiplication via the converter.
I don't recall if all the AT cars would, though, but 2 stand out in that regard. Most all had 3.23 SG and got radials for street driving.
Of the 2 383 4-speed cars I currently own, one is markedly stronger than the other, but it was blueprinted with NHRA-max CR from its days as an F/Stock car and the other is a stock rebuild.
Both currently have 3.23 gears & SG & same tires.
Bring the revs up a bit and both will light 'em off, but I haven't bothered trying that from idle.