525 SC's life expectancy

[Interceptor]

With occasional bursts of high end running and more of a crusing lifestyle what is the life of these engines ?
What goes first ? top end or bottom or everything at once ?

ed

[Griff]

Mine has 380hrs. Redid the top half last Spring at 335 hrs. It really didn't need it, except for I had a pitted valve from an exhaust manifold leak. I also wanted to add a little hp and chnged to a roller cam.
Bottom is untouched. Only uses 1 quart of oil every 20+/- hours. My driving habits are about the same as you describe. I would expect the engine is good to go for another 300hrs.