2025 Ram 5500 Chassis CabThe next truck on this list is not a traditional pickup truck. Instead, it is a chassis cab. The 2025 Ram 5500 Chassis Cab falls just a little bit behind the Ram 3500 in terms of maximum towing capacity, but the difference is very minimal. The reason they are so close is because the two trucks use the very same engines. Once again, the standard engine for the truck is the 6.4-liter Hemi HD V8 engine, but with this truck, that towing capacity is higher than the 3500 at an impressive 21,240 pounds. However, if you have the high output 6.7-liter Cummins underneath the hood, you can expect that capacity to increase to 34,540 pounds.That slight decrease in towing capacity comes with a commensurate decrease in power output, as the Cummins makes up to 360 horsepower and 800 lb-ft of torque in the Ram 5500. Like the Ram 3500, getting this upgraded diesel engine is going to cost you a pretty penny. If you're happy with a base-tier trim, you are looking at an additional $9,495 charge for the Cummins engine. Unfortunately, you are out of luck if you want the Cummins to come as standard. Even the Ram 5500 Big Horn crew cab model comes standard with the 6.4-liter Hemi V8 and requires you to specifically select that you want the Cummins. On the positive side, the Cummins is available for every trim and every cab size for the chassis cab truck, so you can get that 34,540 pounds of towing even if you don't need a traditional truck bed.