I haven't blown one myself, but I have had a few around me go. My Dad's 82 K-20 Chevy 6.2 diesel broke a valve spring, dropped the valve, exploded the piston, twisted the rod, and windowed the block to the outside and the inside. You could look through the hole in the block and see the camshaft. That was two years ago. Just out of high school, My buddy and I transplanted a well used 70' 455 into a 73' Firebird, and proceeded to beat on it. It started to make noise, so we headed for home, and it blew the bottom end out. We skidded through our own oil and antifreeze. When I was in high school, my cousin ressurected his Dad's old 68 C-20 Camper Special with 411 gears. After he spun a bearing on the original 327, we dropped in a series of $100.00 Peddler's Post 350's and one by one blew them up too. Neutral drops with 411's and worn out old motors don't mix. When I was just out of high school, my uncle had a late model race car at the local 1/2 mile. He had a nice John Lingenfelter prepped 327 that we used for a couple of seasons. Over the winter, the block didn't get completely drained, and it cracked around a freeze plug. My uncle is an expert welder, so he welded the crack. What we didn't know, was the appearently the block was also cracked on the inside, and at about 6200 RPM up the front stretch, she came apart in spectacular fashion. About the only thing we salvaged was the intake, a valve cover, the carburetor, the water pump and the flywheel.