Check out the following links for Piper parts for auction on ebay:

Piper J3 Cub Fuel Tank:
http://cgi.ebay.com/ebaymotors/ws/eB...%3ALC%3AMT%3A1

Piper J3 Cub Boot Cowl and Cowl Assembly

http://cgi.ebay.com/ebaymotors/ws/eB...sPageName=WDVW