Mr battered YZF

Hi I've got a Yzf 750 1993, it's got a blown head gasket, burns oil and has low oil pressure. So I wacked another engine in today from a 96. It's got the 1993 engines carbs and ignition. It turns over, but does not attempt to fire or start. The last engine run fine. Any suggestions? Are there any differences between a 93 & 96 engine? Ignition timing? Please help