Combines Throat question

we are told you should put a protractorIJ on the rear of the head and in the field the angle should be 10-11 degreesforward tilt if not in field but yard add 1 or 2 more

My best friend had 1020 platform on 1680 with same problems. He traded for 2388 and kept the platform-he still had the same problems.I would cut beside him with 1680 and 1020 with no problems. I traded for 2366 and kept platform with still no problems. He had 6 different prople from Case try to fix it -no one could ever do it. He finally got fed up and traded it in the middle of 80 acre field. That solved the problem. I suppose it is possible to get a lemon in any piece of equipment. Good luck!