I just purchased one from Larry Stock (PPC, REno). He had a bunch made up by the same guy that produces the Fidanza flywheel. They are drilled for standard 10.5", 11" and the Centerforce clutch, weight 13.5lbs if I remember correctly. He also has lightened steel ones if you want to go mid-way on weight.
I found a 351C Fidanza for sale for $303 over the internet on the east coast and did some research. I found that all Al flywheels are not necessarily the same, as even some of the cheaper Fidanza ones are made from rod not billet. Unfortunately I deleted the correspondence only this morning...Murphy's Law