I did my first 10K lb tow today. A 32' Concept boat on a 36' Rocket trailer from Ft Lauderdale, across state to Ft Myers, FL. The 'ol 6.2 ran about five degrees warmer than usual, and the temp senders on the tranny(SM465) and diff (Dana 70, 3.73 with locker)reported 200* and 180* respectively, on average. Fuel economy with the empty trailer(about 3K lbs.) dropped from the usual 20mpg to around 16.5mpg, and then dropped to about 8.2mpg with the full load. Top speeds in the 55-65 range. Alligator Alley is pretty much flat.

As I'm new to this level of pulling, I'm wondering if my experience is typical, or if those that are more seasoned than I would have cause for concern with this type of performance. I have a 36' scheduled for a pull in the next couple of weeks. It should weigh in about 12K lbs. Am I pushing my luck?

It will do it. You are handicapped a little with 3.73 gears for towing that kind of load, 4.10 would be a little better. As far as fuel economy, sounds about right for that kind of load. Try to find the sweet spot on the accelator pedal, another words back off the throttle until you start to loose speed and then feather it back to where it will maintain speed. That will keep you from over fueling and might help your economy with heavier loads. The engine has the torque to pull, but you aren't in the peak hp range. Once you hit the sweet spot, giving it more fuel will just burn more fuel and you won't go any faster.:cool2:

The engine has the torque to pull, but you aren't in the peak hp range.

Keeping in mind, It's N.A., Is this something that could be remedied with propane injection?

I read an article of a guy with a 6.9 ford, na that made a propane kit and he claimed it increased hp noticeably. I have never tried it but a set up could be made pretty cheap and if it worked well make it fancier.:grd:

I know some people use propane, but I think using propane is pretty close to using a little ether or nitrous oxide. I don't see how using either of them will extend the life of a 6.2L engine. The propane or ether is going to detonate before the injector opens. That early ignition puts a lot more stress on the pistons, rods, cranks, and bearings.

A 3.73 rear end is not the best for your operation. I had a friend that ordered a Ford 6.9 with a 4.10 for trailer towing and he got terrible mileage and performance. Then he discovered that Ford had put a 3.73 unit in his truck. Needless to say, he was pretty miffed. I don't remember the model year, but he found out that many ford buyers had been given the wrong rear end.