I have a 1975 450 SL with 76,000 miles. I have heard a growling sound below the altenator, which I thought was the bearing in the smog pump or something to do with that. Well today when I started the car the pump was froze and the belt squeeled like a pig. I got the belt off and the pump won't turn. My question is how important to the overall performace and fuel economy is the smog control to the car? I live in the middle of Nebraska, so we have no clean air restrictions to deal with through the state motor vehicle department. Do I need to fix the pump or can I live without it? If I can live without it, are there other things I need to do to the system?