What's a good cartridge for infinity black widow?

The chances of finding a Sonus Blue cartridge with a rubber compliance that wasn't hardened by now would be very slim. That's unfortunate as it would be ideal for the Black Widow arm(I had one in a Magnepan Unipivot I way back when). Replacement styli haven't been avaiable for those for a number of years either, Sonic Research having gone out of business long ago. Here's company that offers a variety of older cartridges: (http://www.adelcom.net/cartridge.htm)

I remember getting good results with these 'back in the day' with an Ortofon OM30 and OM40, both of which are still available. The mounting, height, weight, and compliance all worked out great for this arm.

If you can find a Sonus Blue Body...I bet soundsmith could fix it for you

Thanks so much for the imput, I have ideas's now as to what cartridges to look for. Is this hobby fun or what?

I wouldn't put FUN as the first word to describe this hobby. Expensive, frustrating, disappointing, and tedious all come before "fun". I am a private pilot...another "fun" hobby. It's only "fun" after you've landed at the place you wanted to without denting anything.