Apparently there was a design change for this part early in production of the MGA (1500). The first picture below shows he early design, while the second picture is the later design. There is no change of part number in the Service Parts List so the second one supersedes the early one as a service part.

Early 1500 part above. All later pushrod engine cars part below.

For the concours conscious folks there is an interest in when this design change occurred in the course of production. My first two guesses are, after the first 500 cars, or late 1956 at same time as change of the dash instruments (and other things). I am hereby soliciting for information fro early production MGA owners to check their car and let me know if is has the early or late shaft design and the chassis number of the car. I will tabulate the results here hopefully narrowing down the time window for this change. The starting point is now for cars before chassis number 19000.

Accelerator pedal design change: CHASSIS NO EARLY DESIGN LATE DESIGN NOTES HDExx xxxxx X HDD43/12603 X Built Mar 4, 1956 14408 X Built Apr, 1956 HDL43/18917 X Built Aug 24-27, 1956 19357 X Built Sep 3, 1956 HDL43/22885 X Built Nov 1956 27650 X HML43-31994 X