Look at the serial number on the side of the case above the pan. This can be looked up to find out what year it was made and used in.
I'm thinking small block. Measure the top two bolt holes and if they are 6 1/2" apart center to center, it's for a big block.
part number 2466148 is for 1965 B,C body 383-4bbl,413, 426 street wedge 727.
Matt