I have a 4.3L and 700R4 w/ shift kit in my truck. I've got no cat, flowmaster 40 muffler, EGR removed, injector pod spacer, hypertech "salad bowl", and K&N filter, and electric fan. Timing is advanced 8 degrees. I towed a car on a trailer weighing 6000 lbs total from Wichita Kansas to St...