340 Gets Terrible Gas Mileage

I would like to find one that will stay on the damper. Two have flown off my new damper....:BangHead:
The one from mopar perfromance stayed on pretty good. That was in 1990 or so. The black background made it easier to read.
The current engine has a non-mopar diameter damper so I had to try different brand. It didn't stay on that long. I don't know if the difference was the prep or the adhesive. I have a couple more to try - when I get 'round to it.