I had a 93 Dodge 1/2 ton, club cab long box that was 318 with dual fuel (gas & Propane) . . . gotta say, it was a DOG on propane . . . I never looked at anything, cause it did run so well, but you would have to manually take it out of overdrive in order for it to maintain speed on hills, when it was running on propane. Did not get that great mileage on propane either . . . it probably needed that timing advance to get it running better on propane. Good luck with it . . .