I have a 05 Ford 6.0 Super Duty E350 with a VERY mild conversion pkg. Done to my request by Tuscany. Before anybody says anything bad about the 6.0, yes, I had lots of problems with it but it is now bullet proofed to everything Ford did wrong. It also has the SCT Livewire programmer in it. Before the mods I towed 9,000 plus lbs. of trailer, 38 foot. Last trip was from San Antonio to Ohio and then up to Wisconsin and back. No problem towing the weight or length. Have not towed with it since the repairs and modifications but expect it to do even better. Supposedly you can still get the E350 with the V10, but the van is the only thing you can get it in.