fzr600r replacement engine

mate has just bought a fzr600r race bike with a rod poking through the crank case .... not very nice, when we are replacing the engine can a thundercat engine be bolted straight in (physically they are identical) but it's the wiring loom and carbs exhaust etc..... i dont see there being much of a problem but any helpl would be appreciated.

p.s. the broke engine has a tuned head, although i haven't lifted the head yet to see where the piston is burried

thanks

Crow