ford 10 cyclinder engine
We pull a Cardinal 33RLWB. Probably about 11,000 loaded. Use a F-350 V-10, 3.73 gears and have had no problem. I have even pulled up 6 and 7% grades. Mileage isn't great. I get (towing with AC running) around 9.2 if everything is good. PLulled into a head wind this summer going up in New Mexico and got 7.25 on the worse tank. I've put in a chip and get close to 15 when not towing on the highway.