This looks pretty encouraging.
http://www.mckenziecorp.com/dehydration.htm
There looks like there is a small mistake in teh chart for Btu/gal, but other than that it seems to have some FANTASTIC properties for a performance engine. How about 120 Octane, and very high energy density (btu/lb). More research is required but this could be a fascinating project for the Vette. . .
Unfortunately, while CNG is a completely organic and nontoxic gas, due to the genius laws of CA, the conversion would be illegal as it is not the engineered fuel for the engine.