The engine's vertical position has always been determined by the oil pan and the bottom tubes of the QA1 K being on the same plane, for obvious reasons. The pics in post 142,143, they were taken with the oil pan and K resting on the floor.
The pics above, the pan may be ~1/4" lower than the K but that's pretty much what you're seeing here. Fabrication tolerances will come into play as well, so if engine winds up a little lower, well the CG will love it and I won't complain much about adding a little skid plate.
The pinion angle will have some say on the final driveline height, so next on the list is getting the trans bolted to the bell housing.
