I have a 2008 4l80..its actually a 4l85 because of the 5 planetary gears, but most people say this isn't a weak link for the 80e anyway. I've seen some builders like Jakes prefer the older cases but he does a lot of custom touches to his, but I like having the split cooling lines on the newer cases. There are some issues that may be exposed after the 7-800hp mark, but as of now my cammed 6.0 doesn't seem to make my trans break a sweat..I would recommend a reprogram kit or dual feeding the trans to get the full holding potential out of it.