87 was known for Head Gasket blown. Fixes were run a copper gasket. Increase studs to M10. I just used the paper gaskets and tighten it down more than specs. Also, no matter what you use, check bolt tightness regularly.
The cylinder ears were known to crack. Fix is to weld them and reinforce them.
Detonation. The stock dome size and shape can detonate when running pump gas. Best fix is to get it reshaped and possibly run higher octane fuel.
Another thing is vibration. Many say the head stay can cause issues when the engine is vibrating badly. This is what can lead to the cylinder ears cracking, and possibly other things. Many just don't run the head stay.