Thinking out loud..

I would set it up 2* down on ladder bars. Pinion at 1* Down depending on where your driveline sits & take off the ARB until you figure it out.

How about your front suspension? Are you getting full travel out of it topping out the shocks on launch? Is anything binding up?

My little Scamp feels like it Pulls the front wheels going 30 MPH in second smacking the Juice. I have a lot of front suspension movement it tops off right away. Loose as a goose! Its on Mono Leafs and caltracs though. Caltrac 90/10's up front and RMS Adjustable Strut Rods with Heim Joints.