since you are taking off your head, it is always a good choice to put a new timing belt on, plus i am not sure but the timing belt may be a diffrent size when you go and swap heads, someone correct me if i am wrong. Also on manual hondas, if the timing belt breaks, you will have to rebuild the engine, because the valve will stay open and the pistons will hit them and bend a valve or break the piston, conection rod or what not. Just change the timing belt, it is cheap insurance. The honda oem ones are like 50 if not less, and the aftermarket brands are even less.