That is an idea. Just keep the V8 and convert it to propane. I am interested in getting this car:
1967 Cadillac Fleetwood Brougham
I wonder what the cost to operate the vehicle would be on propane compared to gasoline. Also driving range would be an issue if say I take a trip across the USA and need to find places that sell propane only. Ill bet that cadillac only gets 9mpg on gasoline. Probably would need a giant propane tank to tow behind the car kind of like the space shuttles booster rockets.