Originally Posted by gsxr

You'll have to swap the pulley for sure, as the offset and diameter are different.

You can't tell if you need to re-clock until you compare the back of your 143A unit with the existing alternator & brackets. The new alternator doesn't need to have the terminals in the exact same location, they can be slightly different; as long as no brackets or pipes interfere with the wiring, AND the wiring is long enough to connect. Don't forget to replace the tiny stock B+ wires with larger cable similar to what is shown in my photos.