The Styrofoam model was used to create a steel "test frame", which had to stand up to several standards: have a speed of over 100 mph, go from 0 to in 5 seconds, possess a steering system to make sharp turns at city corners, and to withstand a self-propelled launch of up to . On the first jump test, the Tumbler's front end collapsed and had to be completely rebuilt. The basic configuration of the newly designed vehicle included a 5.7-liter Chevy V8 engine, a truck axle for the rear axle, front racing tires by Hoosier, rear 4×4 mud tires by Interco., and the suspension system of Baja racing trucks. The design and development process took nine months and cost several million dollars.