[jon@harrison.ne]

The measurements being discussed here do not address the angle between the the crankshaft centerline and the transmission centerline. In other words, they assume that the plane of the bell housing is orthogonal ( i.e. perpendicular ) to the crankshaft axis. This is probably a good assumption for a bell housing with machined mounting surfaces ( housing to block and housing to trans). This is not the case with some of the stamped bell housing / scatter shields that I have seen. I took mine to a machine shop and had the trans end milled parallel to the block surface. When I watched the operation it was obvious that they weren't parallel to begin with.