Found a member here, borland, who has done this.

http://www.bikeforums.net/showthread...-21T-Freewheel

He also references a write up about the conversion with modified 17 tooth sprocket here http://bellsouthpwp.net/k/a/kaeru41/freewheels.htm

Finally, here is write up from bikepro.com about the conversion with the addition of making it into an 8 speed freewheel.http://www.bikepro.com/products/freewheels/tnt.shtml

Here is borlands picture.


I realize at this point I am basically writing to myself on this thread but after spending a lot time searching all this stuff out there might be some values to others someday to have it referenced all in one place. At least I'll use it.