[Trevor78]

A 3-row water pump pulley with non-AC says possible smog pump engine as 3 accessories still being used or they'd use the 2-row pulley. On Olds engines with smog and AC, the compressor belt would bypass the WP and go to a 4th row on the crank pulley.

With only the 2 accessories remaining it won't matter anyway. These engines had the pulley offsets changed around and with extra rows when the need for extra accessories became more popular. The water pump length became standard rather than different lengths of earlier engines.

Another obvious way to detect a smog 403, other than blocked-off intake fittings and carb used, is the curved oil filler pipe required to clear the smog pump. Regular just used the straight tube. The original accessory status is more for swapping pulleys around and knowing which will line up together even if the accessories are long gone.