Yes! There was a drop in power that was somewhat noticeable. For instance, I always drove in 3rd rather than O'drive around town. Passing on the highway was a bit different than on gasoline. Switiching from gasoline to CNG advanced the timing quite a bit too.
The system was OK for a full size car like a Caprice, or Crown Vic, or any trucks. Today's tanks are made from composite material rather than thick steel I believe.
Propane is a different story in that it is not such a heavy system. Not as safe though.
