I have seen that Mustang 360 article.
The frame and block brackets are fairly easy to come by. The rubber isolators are unobtainium.
With a slight modification, a set of 67 Dodge Dart 6 cylinder isolators can be used on the 250 brackets.
Go to Rock Auto and look the Dart isolators up. The left and right side are different, you want the one with the thinner rubber.
If you get as far as having the parts in hand, I will show you how to make them work.