I believe you are correct on the thread size of the smaller thread. I know it was smaller and was going off memory and just had surgery and taking pain meds so my memory is clouded. How many large thread 29 spline 741's have you seen? I haven't seen any. Not positive but I always assumed that in 40 yrs. of working on them and not seeing any 29 spline 741's they didn't make them, but maybe it was just luck of the draw.
