I tried all the auto parts stores in town, napa could get one for about $218.00, and oriellys got me one for $100 and a core exchange. it was a remanufactured one, ironically they had one available in an oregon warehouse... the first one I got from them started pushing fluid out the back upon bench bleeding, but the second one they got for me worked perfect.
the other auto parts stores could only find rebuild kits.
you also need to be assertive, tell them you need it for a 66 60 series (my example) and help them along in looking it up. the first lady I talked to at oriellys found it right away, and when I went back when I had the cash, the guy I delt with couldn't find it, I had to walk him through it but he finally found it.
when I was at the other stores I had to help the guys look it up in thier books, and the guy at napa kept having to be told 60 series, not 10 series
I really wonder if the m/c is any different than the 60-62 c/10-30... the core I ended up giving oriellys was off my 61 c/20, but the cylinder bores measured the same as the bores off the 66 c/60