A "classic pit bull" as you referred to them as most certainly do not look like the dog the OP has pictured, and they certainly do not typically weight over 70 pounds. That dogs features and size are very similiar to that of the American Bulldog.
Mis-identification is one of the most prominent factors of the American Pit Bull Terriers demise. Anything with a huge head and a short coat is NOT an APBT. People are too confused nowadays with the 'American Bully' dogs all over the place with their twenty something inch head and bowed out shoulders. Most of the old school original lines of the APBT do not even look like what Joe Q. Public THINKS an APBT looks like today.
And yes, as MrBubblyDrink clarified, the American Pit Bull Terrier has LONG been a registered breed.