I just passed emissions testing with my nephew's 90 SC without SC belt. The car quick passed, and was done so fast I thought there was a problem. I don't like the way illinois tests the cars on their dyno. They don't open the hood and use a dinky fan. Once the car goes over 45 mph the fans shut off, then you have to rely on their dinky house fan. My 89 SC blew headgaskets last year the day I got emission tested. Now I don't think the gaskets will blow if you get your car tested as mine were on there way. The overheating of the car on their dyno just finished them up.
An interesting thing happens when you run the engine with the belt off, when you rev the motor the engine will spin the SC once you lose engine vacuum and the bypass closes. I don't think this will hurt anything although I'm sure the engine will lose some power, but with out the belt she's weak anyway.
Jerry