I have never bought anything that said Dorman on it that fit anywhere near right. If you bought a lawnmower wheel from them, it would probably turn backwards.
Hard to find true custom tuning for the 7.3 nowadays. They sell them as custom, but most of them were made custom for somebodies truck 15 years ago and just sitting in a file now.
And then clean them out really, really well. You do not want any little metal shrapnel left in them at all. I used a small round file to clean it out and then a pistol cleaning kit with to push an oil soaked swab through it a few times.