I believe Detroit Speed was involved. Here is a link to a spec sheet on the motor. I could not find the post where he said who was doing the work, but I found where he indicated the Mule and the Red Witch were off in Detroit getting some work done. The Mule name came from what Mark Stielow called the car when he was building it. Coolest license plate I have seen is the one Charley has for the car "El Burro".
https://www.yenko.net/ubbthreads/show...0/fpart/3/vc/1