We have no CNG stations in Waco but the gas company has one for their trucks which have been all converted. They have a mix of F150 and chevy 1500 pickups all running on CNG. Yellow cab here run all their Crown Vics on Propane. Their mechanic says running on propane does not cause the engine oil to get dirty like using gassoline. Another possable benefit from using lp or cng, longer engine life (if done properly) This conversion still may allow for gasoline or gas at the flip of a switch. You can convert diesels to cng also but then they cannot go back to diesel since you replace the injectors with spark plugs and the injection pump with a distributor and install a cng carburetor in place of the air intake or so I am told.