The CalTracs are the eighth wonder of the world. My 408 with 3500 stall & a small NX shot in a '73 Dart will yank the front wheels and dig straight out of the box every time. It is so easy I trained my 16 year old Son on how to launch without a concern. I don't know if my combination just works or if every CalTracs dials in so well ~ but I am a believer.