This was 10 yrs ago but thought it might help someone, I put a 68 Chevelle SS rebuilt 12 bolt in my car about 10 yrs ago and had the DS made with 1350 joint but I didn’t think of that upgrade when I had new perf axles etc put in the rearend so made my own U joint out of 2 just need to watch for China Creep in these parts that use to be normal US parts