I googled and found some trucks that look similar to your rendering, just for a better idea. Hope it helps. The first two are stock roof height and the last 2 are chopped.

Truck 1 Click Here
Truck 2 Click Here
Truck 3 Click Here
Truck 4 Click Here


1946 GMC Pickup - S-10 Frame, 455 Buick, TH400, original patina.

My 46 GMC on Photobucket