[norman]

My sled has 6500 miles on it and runs great. Should I be concerned about an upper end rebuild?

 

[94ZR580]

The issue to look for is skirt condition, not necessarily ring seal. I can't think of a way to check the skirts without removing the cylinders. When the skirts fatigue they start to collapse and you should be able to see, or at least measure that. If a piston skirt fails it can ruin the bottom end very quickly. Some will say if you take the cylinders off you might as well replace things while you're in there. I've heard of people getting over 10,000 miles without problems on these engines. The call is yours.