By Turbo, it is not the Turbo you stick on the exhaust, to make forced induction. It is a Turbine engine. From Wikipedia STP-Paxton Turbocar The STP-Paxton Turbocar was a racing car, designed by Ken Wallis as the STP entry in the Indianapolis 500. File:800px-STP Turbine.jpg So why did Mattel use the term "Shelby"? Why not "STP" or "Granatelli". Interesting that this type of engine would go on and power many other things, M1 Abrams.