Only real differance is the FWD block has a threaded hole missing from the rear that the RWD crank oil seal housing uses, either drill and tap or use extra sealant like i did got a FWD mondeo block in my Sierra TBH i'd just swap heads over save all the hassle, 90% of the time they will snap the cam in a few places, bend some valves and maybt a cam carrier but thats usually if the belt goes at high revs.
Wip the head and check the pistons, most will have valve marks in then from old belt snaps 1 in 3 i've stripped have had valve dents in the top of the piston