If you Google "Mustang Owner's Club" without the quotes, you'll get the web sites of the Mustang Owner's Clubs of Canada, the USA, Great Britain and Australia. All of those web sites would probably have active Q&A forums like this one where you could ask a question.

Also, if you simply Google "Mustang Forum" without the quotes, you'll get a whole bunch more forums all dedicated to the various flavours of Mustangs; 5.0's, Cobras, fastbacks, convertibles, GT's, etc.