I have not used the conversion ends.
However I assume you can also buy off the shelf tapered ends at NAPA and the like and have the arm reamed to match what you find.
http://www.speedwaymotors.com/Search?query=ball%20joint%20reamer

If I'm ever in the situation I'd surely ream the ends and use common easy to get ends.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-