I'm not good at identifying lengths in pictures, but this truck is more likely made on a ¾-ton wheelbase (125¼" / 3.18 m) or a heavy-duty one (134½" / 3.41 m), not on the wheelbase of a Light Delivery (115" / 2.92 m): clearly not an "AK", for me. But a lot of people (even owners, apparently) use mistakenly that name...

Except for the cab and the (GMC) grille, there's in fact nothing left from the original truck. But even if the engine is not the original one, the 160 mph speedometer is maybe a bit optimistic?