Too much BS for me in this thread. The reason stock blocks crack at "500hp" is because people were pushing them to the limits back we were barely above carburetors and vacuum retard distributors. It got a reputation back when nobody understood a thing about tuning. My last 347 stroker went nearly 85,000 miles with almost 700 ft/lb torque. There are now multiple participants pushing nearly 1000 ft/lb of torque through 30+ year old factory blocks through 2 race seasons.
Kurt
Kurt