i was at ATlas Frame and Axle last week. they had a C6500 truck(cab and chassis) with 22' frame rails behind the cab. I watched them re-drill the frame and re-mount the axle and spring assembley. then they cut the frame off behind the axle to their desired length. they went from 22' to 16'. this is the only reason i said what i said. I guess these old trucks are a bit different.
