It's "rated" as a 2,500rpm stall, but the most I got out of it was around 1,700rpm. Need more torque =P

Yeah the 4L80's weigh a ton, as do their converters. That's why my final plans include a 4L60e because they are lighter than the 4L80's but are still electronically controlled and thus a more reliable overdrive than the 700 or 200.