If want to pull a 30' boat or a trailer big enough for a family of four up the Rockies, then, sure, can want a big engine. Otherwise two of the main things about a "towing capable engine" is (i) a bigger radiator and (ii) an engine oil cooler. The main issue is that when towing the engine can run at relatively high power levels for minutes at a time instead of the usual just seconds; then discover that the radiator is not big enough and the engine oil gets hot. The radiator never was "big enough" it's just that the high power levels lasted only for seconds instead of minutes, and the seconds were not long enough to overheat the coolant.