I just got desktop dyno from my friend and am still learning how to use it. you cant just click and pick the 3.8 sc motor. the program is more towards accuracy. you would have to enter it in as 231ci, 3.81in bore, and 3.39in stroke. Then you would have to know about the supercharger like the flow,speed,and ratios. You would have to obtain all the specifications on the engine before you can work with it.