What do you have for a cam in your wagon? What stall? I need the 3.42 or 3.90 posi installed to be a fair race, 2.78 open won't cut it. The posi is out of stock everywhere, it is a modified Ford 8.8". You mean the new 7.3 is a dog below 4000 rpm? I towed 6500 to 7000 pounds with our work 2011 6L 3/4 quad cab 4x4, anything below 4000 sucked. I pulled the rpms up to 3500 rpm, 70 km/hr to 100 km/hr took forever to get there. These LS trucks are all the same, they suck below 4000 rpm, towing or not. I clearly need to drive one in a car with a good tune🤷♂️.