[My427stang]

It does seem odd, but that's exactly what it is. Otherwise you'd need a different distributor and oil pump.

It does help in torsional strength over the length of the shaft, and theoretically the smooth surface of the majority of the shaft "could" be less vulnerable to stress cracks but that part is really reaching.

I personally have never broken a Ford oil pump drive on anything that wasnt caused by some other failure. However, I do also run an oversized one from Doug Garifo on my 489. The 427 before it and the 390 in my F-100, as well as most any other one I build, I just use a good Melling driveshaft though