[RICK LAKE]

Wazza I have worked on and seen 600hp stock blocks and seen failure just like this. Why are you banging this motor to 7,000 rpms when it is out of power? Your motor got cap walk. With only 2 studs holding the main cap in place. 6,700 is about max for any stock block windsor without alot of filling, 4 bolt mains, girdle and valley support. I would not be surprised to see if the crank is not bent or out of phase, (twisted). The other issue is piston speed, If you are hitting 7,000, your speed with a stroker is out the gate with a stock block.
You built a good motor, but didn't over engineer it. Build more torque. Build a lower rpm motor and lower the ratio of the rearend. You will go just as fast and extend the life of the motor. Just a thought, I have been doing for many years. Some times you need more gears to do this. I have a 6 speed and a 5 speed. Small tracks get 5, big track get overdrive. Good luck with your next build. Rick L.