I've got another theory on the reason a four speed was not available with a 440 A-body. It was likely just a simple lack of available parts (or creativity). An 18-spline four speed in 1969 required a steel bell housing that fit the 143-tooth flywheel. The 383 bell had the two threaded holes for the engine side ball pivot bracket to put the z-bar in the correct location in an A-body. The bell for the 18-spline only had one threaded hole for the threaded stud that was used in a B-body.