I have a 2005 chevy 2500hd 6.0 I tow around 8-9000Ibs it pulls fine if you keep it turning some rpms I was just wondering what is a safe rpm range.I have a k&N cold air intake hypertech programer set to 87 octane straight pipes with an x pipe on it which makes it sound worse than it is when towing

 

my buddies 5.3 when he tows 6000 lbs he has to keep it at 3900-4200 to pull large hills

 

that the nature of the beast. our 6.0 is 3000 rpms at 70-75 and 6000 rpms when you hit a hill.

ive been told the higher rpms are better for it under a load than lower rpms.. something about more oil, coolent, circulation and there is a lot more air being sucked in..

My 8.1 turns 4500-4800 red line with a huge load behind it climbing mountains. never a heat problem or broken... its got 135K miles on it now.