To the question, yes these conversion cars can be run on both regular gasoline and propane. I asked this question some weeks back about propane.
Not this week, but next week I am going to the propane dealer that offers this conversion to check it out more thouroughly here. Gasoline just hit $4.76 a galon.

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Insanity: doing the same thing over and over again and expecting different results.

2006 - Suzuki Gran Vitara (2.0 L fully equipped) Like this car so far except for trying to put on the seatbelt.
1988 - 190e - 2.3L - 172K miles (It now belongs to the exwife)
1999 - Chevy Blazer LS Fully Equiped - killed it June 2006
2001 - Honda Civic EX - 68K miles (sold June 2004)
1963 - 220S - Dual Carb 6 cyl. (sold)
1994 - Yamaha WaveRaider (fun to ride)