afaik if you have the Monza 2 rims that came with metal valves, you'll have to buy and use the same type at replacement time.
i have a spare monza in the garage and the small valves wont fit it this is whats made me ask the Q,
If I remember correctly the early 18" Monza II's had to have the metal valve, but this changed on later Monza II's to standard valves.