I have and LS1 (actually an LQ4) with T56 swapped into my 1986 Camaro using Spohn motor mounts and a custom cross member. I have the rear of the trans raised as far as practically possible to minimize the front u-joint angle. I also have an adjustable torque arm.

What driveline angles are you guys getting with similar swaps?

I can't get my front angle under 3.7deg. Which seems too high. I have the rear set to about 3.2deg.