[wagonman76]

My experience is that the longer stroke does help. I noticed this over 10 years ago, long before trying to hypermile.

The only difference between the 2.8 and 3.1 MPFI engines is the stroke. Same everything else. With all else equal on the car, they run off the same ECM and chip.

I have had several A-body wagons and sedans with these engines and in every case the 3.1 has a lot more torque and gets better mpg than the 2.8. All had the same trans with 3.33 final drive. Miles on the engine did not matter. The 3.1 can climb most any grade in OD and seems to move along effortlessly. It feels like a workhorse, like a diesel. The 2.8 is pretty much hopeless in that department.