I was givin a higher number (HP) consumption by the C6, but even 30 seems big to me. We're thinkin' about a 475-500hp stoked build.
Scott, I tried to confirm my numbers I gave you but couldn't find a solid source to recite. My info was given to me by a friend with vast experience in the hot rod and off-road building. The C-6 has the same weaknesses as the C-4. The planetary set needs to be upgraded to a 6 gear set. The clutch basket needs to be machined to pack more clutches in it, that with a worked manual valvebody and some trick servos will make it gooder. Or you could go to an AOD and drop your ring gear a bit more. I'm sure the C-6's heavier case and other internals would be more reliable but I would find a good tranny builder and ask their opinions. I know of 2, Art Carr and Hughes performance. I know there are others, those are just the ones I can think of off the top.