Do you have any more details of the T56 Magnum swap? I have contacted several vendors that say it wont work (i don't really believe them). Have you seen the Magnum XL they have for the Fords? This may be the ultimate upgrade for us as it comes with a long tailhousing to eliminate remote shifter requirements. Tremec will be releasing a GM version soon (they don't get more specific but I do have an email out to them). I would like to get this squared away before swapping the dif so I don't have to buy a driveshaft twice.
That C-clip issue on the trunion upgrade was a bit alarming (bc I have them too). Has this been a common issue? Or were there some abnormal circumstances in your build?