i have an ion with a stock feedneck i recently baught a cp clamping feedneck thigny but cannot unscrew the stock one ive tried using a strap wrench and it doesnt seem to help.
this may be a job for a vice then,just put abit of rubber round the feedneck then put it in a vice and turn the marker to undo,it may damage the feedneck but as you have a new one it shouldnt matter,dont forget to loctite the new one in tho