Both lentech and Art carr make AODs and adapters for an FE. Kinda pricy though unless you needed a tranny rebuld on the one you have. Also gear vendor is pricy too but if your C-6 is in good shape then its cheeper than the other two.
Leadmic

 

The Gear Vendors is actually more like $3000 once you pay the sales tax and have the rear driveline length modified. The unit by itself is about $2500 before tax and install, depending on application. I've been keeping my eyes peeled for a used one to fit a BW 13-56 transfer case for my F350....

 

If you are wanting to spend around $3500, and have a direct bolt on. Try these guys.

http://www.fbperformance.com/viewtrans.asp?TransmissionID=44

 

Gave up on E40D conversion to non computer truck, to costly. So going back to C6. Anybody know if the E40D torque converter will work in a C6?

 

No it won't. You also just brought back a 15 year old thread.