Building a Sledge.....engine sizes
I know that a OS 46 SF and an Irvine .53 will fit in the same spot.... I believe a TT 46 has the same exact mount.... So I believe it will require no changes.....
I know the bearings for the TT 46 and OS SF are exactly the same... Just stold a set of bearings out of a TT 46 for my OS SF... Worked like a charm!