lawnservice, the 318 can't hold a candle when towing compared to the 360. I worked at a marina and the manager owned an extended cab 99 dodge ram with the 318, we tried towing a 21 foot boat but the thing had no power whatsoever going up even the smallest of hills. When we went to pick the boat up we used my dads extended cab, 97 ram with the 360 and it towed it no problem and never required the full throttle to get up the hills that the 318 did.

As for the 5.4, I've only driven one in an expedition and it had some great power, never towed, but I'd say mileage wise and power wise, the 5.4 is the choice by the numbers. Drive them both, bring something to toss in the back if you must and then drive them again. Why is it that a family looking at minivans can bring 6 children, 2 cousins, teh family dog, and themselves to test drive a new car or minivan, but we can't bring a small trailer or some type of load to toss in the bed of a truck to test out the capabilities of it?