Diff ratio

[Not Anumber]

My car can pootle round town at 30mph in 5th and i often tend to pull away in second as it just means 1 less gear change. I cant find any identifying marks on the diff to tell the ratio. Based on the above should i assume its a very low ratio diff and think about changing it or is this quite normal ? I'm running 2.0 Pinto with type 9.