this is the one I used for my 66 dart using scarebird setup. (I used it on a 65 satellite also, it had a 1 1/32 wildwood master on it and was terrible!) the plymouth now stops better than ever . it does have a longer push though. about 1 inch more than the other one. A LOT easier to push! there are a couple more that I have used this master on and they have performed well also. it's from a 73 dart 360 disc/drum combo.
http://www.rockauto.com/catalog/moreinfo.php?pk=966993&cc=1499091