Stock shafts. The trouble with going with a billet main shaft is that than you will need a billet input shaft to. the only reason the main snaps is that it necks down to the same size as the allison output for the T-case to slid on. The rest of the shaft is way beefy. Beefier than any Allison 1000 shaft no matter what duratothemax thinks. :coolspot:What are you running for shafts on the ZF now john?