The bottom ends (Crank bearings if i remember correctly) are different between the two engines, there are many small changes in them but from what i've read the head will fit straight on and all will be ok.

Although by the time you've put a new cambelt and headgasket on it etc (Recommened if you're having the head off really) I'd sooner put a whole engine in just to be on the safe side.

But if money doesnt permit it then just the head would do.