13.20 mph

Tough to give you input when we don't know what the car is... weight, differential, suspension, etc. Is it an AMC with an AMC 360? Javelin? Gremlin? AMX? Matador? Hornet?
As far as getting into the 12's, it's almost there now... you can pick up 2 or 3 tenths with driving proficiency and air quality.