Jim,
This thread some time ago now, may help.
http://www.mapleleafup.net/forums/sh...t=Ford+muffler
I looked for the guy (in USA) that made my CMP muffler to order, but looks like he isn't on ebay any more. At least my original link to his sales is no longer taking me to his wares.
I'll keep looking.

The above photos are the muffler I had made to specs acquired from folks on MLU.
If I can track down the manufacturer, they can make to your exact requirements.