I am having a difficult time trying to get information on a CNG Bi-Fuel Conversion for an '01 Excursion w/ 6.8L V10 in California. The only info I have been able to find is Holden Fleet Services and if there customer service is an example of there work I want nothing to do with them. They quoted me $15.5K for the conversion. They are probably using less than a $1K in parts.

Is it possible for me to buy a kit, install it my self and have it checked and or certified for CNG refueling?