Smog pump driven puley on camshaft?

Hello everyone, I just replaced all my cam seals on my 82' 308 and I did not have the ring nut socket for the smog pump pulley on the camshaft and the nut broke. I am having a heck of a time trying to find a new nut. I can't find it in any picture in ricambi or any other site. I measured the nut shaft size and pitch and it seems to be a m17 x 1.0. It is also a thin profile nut. I also can't find a standard hex nut. Has any one else ran into this problem? Thanks for any feedback.