What's in this Barracuda?

If it bangs hard from Neutral to Low, at idle, then the throttle pressure has been cranked up, which points to a shift kit.
If it starts in whatever gear you put it in, the VB has been modded and points to the possible elimination of the KD mechanism.
If it barks the tires going into second at WOT, yur all set just drive the nuts off it.

But if the engine revs up between shifts; STOP! That ain't right. Go get you a KD mech and try again.