ShinerBock wrote:
Stock 2003 Cummins made 235 hp if it was an auto and 305 hp if it was a manual HO. The 5.4L in the Super Duty made 300 hp at 5,000 rpm. 3800-4200 is more than the 30% higher rpm you stated earlier. Lastly, I have towed 5-7k with a 5.4L SD and I don't remember it ever being below 4500 up hills. Maybe on flat ground, but not on hills.
The 235hp was California. Mine was 250hp. That was peaked at 2900rpm where it was starting to run out of breath. The 310hp 5.4L makes 287hp at 4200rpm. That's right at peak torque rpm where it's just starting to come alive. The 2010 lowly 5.4L out tows the 2003 SO Cummins.