how far down the the k-frame hangs (post 31, last picture. See how high up the K-frame assembly is in the car compared to the radiator support?)....or maybe better explained....how high up the motor/trans gets installed.
To gain ground clearance for the builders that want a very low stance, some raise the tunnel slightly, maybe 2"...or more, and kinda suck everything motor, trans, exhaust, suspension upward into the car.
not so much a out-of-the-box build....but the results can be spectacular!