Was in the same boat you are.

Sounds like you got the v-6 wows.
The v-7 is the worst engine i have ever owned, it is extremely unreliable
The .12 car conversion was not as easy as it sounds
Try contacting matt at http://www.ballistictechnology.com/ He might make you a custom carbonfiber crutch for your car engine and custom gearing system.
But, I converted to electric and never looked back.

Good Luck