Bolt size at turbo
 

I have done a search and come up with several different answers. I need a new fitting on my greddy turbo becasue the one that i have is not the right size. I am not using the banjo bolt but a 4AN fitting on the other side going to my oil feed line. I ordered a 1.25 X 10mm Earl's Performance Plumbing fitting but it messes up the threads of the fitting when it goes in. What is the right size and any ideas of where i can get the right one?