Quick model of a 70's Chevy Stepvan P30. This particular model has a GM 350 engine and automatic 3 speed transmission with an 11,000 lb rated rear axle and aluminum body.
Many individual parts pulled and combined from other designers to create the main parts of this model. So many parts are used from others that I do not have a comprehensive list. If one of the parts is yours and you would like credit given in the comments just let me know. Not perfectly accurate, but close enough for general feel and approximation, and for how the parts mostly fit together with these trucks.