Hello I'm new to the Forum. I'm hoping that somebody can help me identify my red 80's era Bianchi frame. I'm attaching pictures and I know that it has an Italian threaded bottom bracket as well as made in Italy, and Columbus Tretube stickers. Also, you'll see in the pictures that the serial number is at the top of either side of the seat tube. As best I can see the numbers are 4D and 610. The dropouts are labeled Bianchi. Any help in identifying the model and year would be greatly appreciated!