Yes, it's probably from a '61, which only had three speeds available. The four speed showed up the following year. I believe this bellhousing used a Borg Warner T96 transmission.
I bought a brand new long block Olds 215 back in 1967. After sitting under a table in my home garage for 50 years I sold it to a customer that needed one for a 1962 F85---it's original home. He is a very happy camper.
Thanks for the info, but its not for a T85 or T86, I have those. Looking at pics on the net it looks like it for a T96. One I never heard of.
Yes, that is the early 3-speed transmission bolt pattern. Pictured below is the later dual pattern bellhousing featuring both 3- and 4-speed bolt patterns: This will work with pre-metric ('88 and older?) GM T-5s from multiple HAMB-unfriendly donors.