I am on a road trip at the moment with an AD pickup loaded with a camper and grossing about 9,000 lbs. The 261 does just fine even though it's a bit peaky with ~254 degree cam, about 220 at 0.050 lift. The only reason this works on the road is that I'm running what amounts to a 10 speed plus 3 ranges of compound low.
I'm really curious what you're running here; a T5 with deep under Browning?
