If your intake manifold is showing 8 degrees, that's WAY off. The intake is normally made at an angle 3° to 5° so when the engine is tilted down in the rear, the intake (and carb) are level. Try leveling the intake and re measuring the transmission with a yoke in it to see what angle you end up with.
If you plan on some type of traction bars on the rear, then you want to get close to the opposite of the transmission angle and just allow a degree or so for spring wrap up. CalTracs actually work by using a little spring wrap up, so they can have a couple degrees to allow for. Ladder bars allow very little so you don't really have to allow for any spring wrap up.
Young enough to learn ... too old to remember.