Marty had one of these gas caps at home

http://www.fasteddysports.com/?page_id=3&product_id=838

tried putting it on my 07 and would not thread on, works on both his older america and SM, i think one of the pop ups that eddy sells will fit but i think i remember someone in here saying how you could make these ones fit? something to do with filing down the thread or something, anyone do this? pis or "how too" if available? Otherwise i will go with the pop up one. thanks.

2007 Speedmaster and miss it! 2013 T-Bird Storm and Luvin it! Catching a yellow jacket in your shirt at 70 mph can double your vocabulary