what happened to my 342 stroker?

The other night I was out driving around and ran 2nd gear up to 6k. It was at that moment I hear a loud bang then some clatter clatter afterwards. My immediate response was... oh *****!. The engine didnt stop running but continued to run the car. I was 2 miles from home in 30 degree weather at 2am so I wasnt about to walk. I figured it was toast either way. I drove the car for the next two miles to my home. So anyway, last night I pull the engine apart because there is a freaken hole on the side of my block. My first thought was maybe a spring broke and dropped a valve? I take the valve cover off and the spring is fine. Then I remove the head. The piston has a slight crack on the bottom side (referring to the header side of the piston). The head has a slight marking on that cylinder. So what gives? There is a hole in the block and a hole in the oil pan and I knew I threw a rod. What I have is a CHP street fighter 342. I would have imagined that this engine would have held 6k rpm's. So now its time for a new block, new pistons, a new rod, and possibly a new crank.

There was around 10000 miles on the engine. I have had it since 03. I have had many problems with this engine. Originally it came from them as a balanced short block. Right away we had issues but soon realized that the balance was off and caused the bearings to go out. We called CHP and they said that they would cover it if it was their fault and would cover the shipping. If it was my fault then I had to pay shipping and cost. I also wouldnt know an answer until they inspected. The shipping would have been $200. I decided to have a reputable engine builder fix it. I didnt want to chance it if they were to tell me something so they could get out of it. Since then it wasnt too bad of an engine. I will have to pull the engine out to check the crank to see what actually caused this. Maybe I spun a bearing? Anyway, I am seriously considering on ditching this setup all together and going with a 351.

i will get some pics today. when looking at the piston, you will see about 20 marks or so in the area where the valve would be coming in. On the head, you can see somewhat of a marking but it isnt really bad. It doesnt even appear that the valves are hit. I am sure they are though. There is just no marking. I will have to take those out and check. Is it possible that I could have floated the valves and somehow hit them from this causing the rod to break?