Hi everyone. Since you guys were able to answer my first question (thanks!!!) maybe you can answer this other one.
What is the angle of the sloped rear part of the Abrams the exhaust grills are mounted to? Is it called the transom? I have seen plans that show it to be 6 degrees but then others say 5 degrees and that's what I measured on a diagram from an ancient XM1 manual. And an old modeller told me he worked at Chrysler until it became General Dynamics. He said the angle was 5 degrees although maybe it changed by one degree with new variants? That doesn't seem likely but then again what would I know? 
So if you have the answer please let me know. Thanks like always!