The c6 would be a bit heavy for a 5.0L. You'd have better luck finding a c4. Also a FMX is an option for the 5.0L, but im not too sure of their track record. The AOD isnt really built to snuff for a motor with any decent power, but it can be built up by any performance transmission shop. With gas @ $2.50 a gallon, its a viable option.