Getting a lot of Ebay question, guy has a 748. I wasn't sure, all I know is my S4.
As far as what bikes your S4 engine will bolt into?
S4, S4R, probably ST4 and ST4s.
Monster motors have different width at the swingarm pivot, so unless the guy wants to go to a monster style swingarm no dice
or whittle down the cases for a sbk swinger