I would think that your plugs will tell the story. I haven't been trying to get an exact reading on my mileage but I have no drivability problems and my plugs are a light tan color so I am happy with it.


1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed


My Chevy Master 4 Door is on the Road!