73' 340/904 duster racestoration

Small update today. Last week i went to do a compression test and found that every spark plug looked pretty bad, so this week i changed them out and took a picture of the plugs.

Also i'm fairly sure that this car has highway gears. I got on the highway with the tachometer and found that at 85mph, the car turns just under 3000 rpm.

Pics of the old plugs: