Nice work,man! Ideally; the rear-end needs to be in, but the angle not yet set; ie. the perches are not yet welded and are loose enough that the tubes can be rotated.The ride height should also be finalized,both front and rear; and the driveshaft should be in too, cuz it is the reference plane. Practically, the earth-plane can be used as the reference , but that's almost as hard. The front angle is usually set to 2.5* or less,but more than 1* between the driveshaft and the transmission mainshaft, with the driveshaft going down to the rearend. That is to say the underside of the driveshaft relative to the mainshaft is 177.5 to 179*. The rear angle is usually set to 5 to 7* between the driveshaft and the rear end pinion, with the driveshaft going up to the trans.That is to say the underside of the d/s relative to the pinion is 185 to 187 degrees. The greater rear angle is to compensate for the engine's ability to twist the nose of the pinion upwards. Soft springs or systems need more compensation than stiff systems. The idea is to have the shaft and the pinion at or near 180* under full power, but not less than 180 which would tend to pull the yoke out of the trans. Ideally, at full power, the front and rear angles will be the same but on opposite sides of the shaft, so that the working angles cancel out and negate vibration. Some angle is required at the front; to make the needles shuffle around, to spread the grease around inside the cups, and so that the cross-pin doesn't hammer out. As the pinion moves from rest to under full power, the shaft will move forward into th the trans, to don't forget to compensate for that when measuring for the driveshaft. Boy, I'll tell ya; I would be tempted to build a special V8, just to be able to use that 6spd. Those are some nice splits:.61-.70-.78-.79-.79.