two compleat 1271 blowers with 1050 carbs belts pulleys $9,000 for both setups

How do you tell the size of the blower, I have a littlefield 14-71? setup for alcohol injection with a small block chev manifold under it , bought it cheap but its taking up room. For sale but I would like to give accurate info to anyone interested.

14:71 measures 19" inside to inside of bearing plates, ie: rotor length is 19"

12:71 is 18.1"

each series represents approx 1" in length difference