Check this FAQ:
http://www.rcproductdesigns.com/EightScaleFAQ.htm
You can get a conversion kit here:
http://www.rcproductdesigns.com/OneEigthScalekits.htm
This is a great thread:
http://www.rctech.net/forum/showthread.php?t=158327
These are the best sources I know. ALL of the guys at my track have the same setup and it's very reliable. We all use the Mamba Max (with modifications) and Neu motors. We have 8-12 1/8 buggies and a few truggies at every race (every other Saturday).