Looked into this a few months ago my self, before deciding it was much easier to by an LPG car instead.

Heres a few links I found, the last 2 are interesting if starting from scratch, Did find a bus and pickup that used these but didnt bookmark them. They are also brushless DC motors (AC if you like) and are the most efficient/reliable, brushed motors have a limited brush life also.

The first 2 are really an easy way to convert existing cars by taking out the engine and replacing it with a cheap DC motor directly onto the existing gearbox. The main problem is the brake servo, heaters, power steering and other systems that the engine powers also need to be changed to run of electric.

http://www.evuk.co.uk/http://www.evuk.co.uk/

http://www.evadc.org/build_an_ev.htmlhttp://www.evadc.org/build_an_ev.html

http://www.e-traction.com/TheWheel.htmhttp://www.e-traction.com/TheWheel.htm

Mark

http://www.heinzmann.de/e/index.htmhttp://www.heinzmann.de/e/index.htm