Having undergone the cracked head problem, I can certainly vouch for the superior 528i of 79, 80, and 81. I have an 80 and 81. The 81 has 335K on the original engine/5 speed trans. Both these cars give me NO problems. However, I had a 77 with an auto trans. Head cracked... Trans lost reverse... both at 128K miles. You didn't mention the trans. The auto is typically good for 125k to 150k, unless superior maintenance is performed. I would not have another 3 liter again, after the superior reliability of the 2.8L. Everybody says 80/81 are the best years for these cars. I would include 79, as long as it's a 2.8L.