Swaps Are EverythingCadillacDuramax DieselStreet Car Duramax 6.6L Swapped Cadillac Fleetwood By DaveT - May 20, 2019 0 FacebookTwitterPinterestWhatsApp Want to make your Cadillac Fleetwood a bit more fuel efficient? Swap a 6.6L Duramax Diesel in the car and let ‘er eat. Air suspension and Detroit Steel wheels will take care of the looks department as well.