Actually, if you can't find a good used C4, you can use a C6 by removing the bellhousing and replacing it with the C4 bellhousing and mounting it uisng the front pump bolts. It will look odd, but it does work. I ran one on my 5.0 for nearly a year and a half before finally trading cars. I honestly think the C6 was a stronger trans in the long run. The only thing you want to make sure of is that you have enough clearance underneath to mount it.
