After reading a lot of threads on the subject, I haven’t found anyone who has done this.
I noticed that the later models in the 70s the factory has added an oil groove on the rocker spindle to deal with lack of oil to the head. So my question is “has anybody replaced T120 rocker spindles with newer T140 spindles with the oil groove? Are they even compatible?
Well, if anyone reading this is interested...
Just spoke with someone over at Baxter Cycle. I was informed that rocker spindle, part 71-3549 (the one with an oil groove), can be used in earlier models (ones using 71-1512), as a better replacement. I haven’t ordered it yet to verify.