If you are looking for performance, Propane is not for you, unless you are injecting it along with other power adders.
True story: Back in the mid ‘90s I was assigned by my Chief and the City Manager to assist Oklahoma Natural Gas with a testing program for using various alternative fuels. ONG would supply all the equipment and fuel and provide mechanics to help the City’s own mechanics install it. We picked the newest police car we had and converted it to propane, 350ci police intercepter engine, Chevrolet. I was to then take it and drive it for a full 8 hour shift, including a stint at our high speed pursuit training track. The results were very disappointing. Normal driving was ok, a bit gutless, but ok. Pursuit driving I could have been outrun by a VW with a good driver. There was a switch installed in the auxiliary panel that switched back to regular gas. Pedal to the floor on propane then flip the switch. It was like hitting the nitrous button.
Test #2; everything was installed to run on CNG. Exactly the same tests were performed. Normal driving was ok, a bit more gutless than propane. But still ok. Pursuit driving for the first 200 feet I could be outrun by a 12yo on a bicycle. Flip back to gas and hang on.
If we never had to use the full potential of the engine, either propane or CNG would be fine but sometimes you just gotta go. Cost savings would factor out at about 8 months to pay for conversion not counting the cost of a refueling station. This was with the grant from OGE if we went with CNG.
Needless to say the City chose not to change their program and still uses gasoline to this day.
Now back to the practical world, if you have the access to propane and the expertise to install the equipment and maintain it then maybe it would be for you. Cleaner oil between changes, probably. Easier starting, maybe. Cheaper fuel, certainly.
This is my personal opinion based upon my personal experience. FYI
