I have an honest question that I'd like some input on. Has anyone ever done the prop end in splines like a drag axle and splined the prop. I don't know that that interference fit of a matched taper could be duplicated for lack of runout. Pro stock drag axles are 300m material which is in the same family of materials as a prop shaft. Gundrill a maybe slightly larger diameter than current shafts for strength and??? Broaching splines can be pretty accurate. Just a question keep the stones thrown on the small side!