Smog pumps were basicaly a lie to fool the test equipment of the day.
They put extra air into the convertor to produce lower #s at the tail pipe, if the cat converors are gone and you don't require emissions testing in your area , removing the pump and pipes will not harm the engine.
All of the BIG 3 used the pumps for a number of years to bring their test #s in line .
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.