Once you pull the heads, look at all four corners. Every 7.3 idi I have had apart has more ring ridge on cylinders 1,2,7,and 8. Alot more. Pulled my heads off of my 89 to do studs and new gaskets to find that those particular 4 werent any worse than cylinders 3,4,5, and 6. I did the 6.9 cooling...