Matteo,
That's an interesting frame you have there. It sure has most of the features of a late 50's early 60's frame. But for that period I'd expect to see eyelettes on the dropouts. The chainstay bridge lugs look like Masi up to 1964. I expected to see the same support/lug design on the rear brake bridge, but they are diamond shaped like the later Masi's and Cali Masis. The seat tube lug cluster also seems short for the period. My 1963 bike has a very long pointed lug going down the seat tube. I'd say it is not a Masi frame even though there is a Masi badge. At least the frame is nothing that went through Faliero's shop.
Teo Michael