Have had a Silverado 5.3 with the 3.42 axle ratio, an F150 with the 5.0 V8-3.55 axle ratios, and two F150 3.5 Ecoboosts with the 3.55 axle ratios. At first I had a KZ CL180 travel trailer (3850 lbs empty) and while this was not a very heavy camper I was not happy at all with the way the Silverado handled the load as it was shifting up & down a lot, engine roaring, and getting 9 mpg. Traded the Silverado for the Ecoboost F150 and loved it as it lugged like a diesel and hardly ever shifted down. On our trip to Alaska the Ecoboost averaged 10.4 mpg which is the kind of gas mileage a person gets when pulling anything. Then I traded the F150 for another with the 5.0 V8 engine, 3.55 axle ratios, and while it was acceptable in pulling the trailer, it did a lot of shifting up & down to do so (still got the 10 mpg). Then we got a bigger trailer, a Keystone Passport 2510RB weighing 4720 lbs empty, and I really did not like the way the 5.0 pulled the new camper so traded for an F150 SuperCrew, 4x4, 3.5 Ecoboost V6, and am happy again. The 5.0 V8 was fine for towing on fairly level ground but on the hills needed to shift down & rev up to get over the hills. I don't tow fast either, usually 60-65 mph. The turbocharged engine pulls like a beast and I like it. I was completely happy with the 5.0 V8 except for the towing part and got the same mileage when not towing with both the 5.0 & 3.5 Ecoboost F150's (17-18 mpg Hwy, maybe 19 occasionally). In no way am I attempting to bash the 5.0 V8 as it is a good engine. Am just telling my experience with towing. Have had turbo chargers on farm tractors & combines for years without any trouble on any of them so I personally am not worried about that, Hope this helps but it is just one mans opinion.