Ram 1500 with 3.0 diesel

Quick question for the ecodiesel folks, I once pulled a 7000 pound travel trailer with my 1997 Ford F150, If I recall correctly little truck had 225-235 hp and 335 pound feet of torque. We're going to visit Cumberland State Park in Tennessee and there was a very sharp grade leading up to the park. I hit the incline doing about 55 mph, I knew where the torque 5.4 L V8 was made, and I tried to keep that RPM as best as I could. By the top of the grade and it was spinning at about 5,000 RPMs, never a problem, but the speed dropped to 30-35 mph by the top of the grade. I had a 3.55 rear axle ratio.

Given the same conditions...would the EcoDiesel with just a few more HP have been able to maintain a higher speed? Or would it have been about the same?

Thanks!

Jeremiah