How Much Horsepower Required to Cruise Comfortably at 70 MPH?

I find a lot of fuel efficiency is not just engine size but also related to vehicle weight. Normally we would say an360 will consume more fuel than a 273. If in the same vehicle & reasonably built the same.

Well, my V6 quad cab ‘03 Dakota gets worse mileage than the V8 version of the truck. The lil’bastard struggles to move the truck and requires more fuel to do the same as the V8, which just makes more torque a bit easier.

For best mileage, on any vehicle, there’s a lot of perameters to be looked at and attended to.