My '91 RT/TT spun a rod bearing while at high speed for awhile (5000-7000 rpm). The stealth was basically stock with a 3 inch full exhaust done to it. It is currently being rebuilt at my shop, just slowly as I'm starting my last semester. A lot of ideas have been thrown around about damaged parts, improper assembly/machining (out of roundness, improper clearances) etc... Lets assume that those variables are accounted for, the motor is assembled/built impeccably. Oil starvation, then, is the prime killer. I don't know what the stock oil pump flows, but, at 7000 sustained RPM, the sump could be pumped dry. A deeper/wider sump and better oil drainage to the sump can allieviate the problem. As soon as the bearing loses its oil film, it's gone to shit.
Now, I don't want to loose another motor this way so I'm looking at a deeper sump (we all know of Supercar Engineering) and coated bearings. No one has mentioned this yet so I thought I would throw it out there. Calico coatings has bearings for our cars from Clevite and ACT. The coating is only about .0002 to .0004 thousandths of an inch thick and it retains oil due to the structure of its substrate. Many people swear by coated parts, bearings in particular. Check out the website at: /www.calicocoatings.com/index.html
Techline coatings (
www.techlinecoatings.com/index.htm) also offer the stuff for DIY'ers. It may not be a cure-all, but, it should add some added insurance.