6 liter V8 Chevy Vortec question

If you don't like the performance of a gas C, look into a super C with a diesel engine. Had 2 different C's with the gas engine an E350 and a E450 and now have a Thor Omni XG32 on the F550 chassis with 6.7L diesel, It has all sorts of power, drives great with no modifications needed for handling and is comfortable and quiet. Oh and very good fuel economy, we are averaging 14MPG pulling a trailer and it never down shifts on hills except for some very long steep grades, set the cruise control and go.