Yes, it should bolt up, but the DC hydramatic (1959-60) is bigger than the Roto 10 (slimjim) hydramatic, so if you are using in a 1961-64 full size Olds, then you might need to enlarge the tunnel. If you need a 1960 DC hydramatic, I have one that looks to be in good shape. PM me if interested.
Thanks for the info. I would like to use the 394 in the 59 Olds so it sounds like that should be workable