[MikeK]

One forgotten point here- The A block has the cylinder bore centerlines offset 0.125" from the crank centerline. This was done to improve the rod angle during the power stroke. The result is unequal piston acceleration forces on the up/down strokes.

Reversing the rotation of an A (or any engine with offset bore centerlines) will turn that beneficial offset into a penalty. Increased rod angularity and severe piston side thrust during the power stroke will be the first result. To make things worse, the primary I-4 design imbalance will make that long stroke A shake even more with the reversed up/down piston velocity profiles.