I think tuning is the key plus setting the engine up for success with lightweight parts. I just had a conversation with a well known small block guy that makes well over 1k hp N/A at 10,000 rpm and he split a Ritter block. He pays a well known engine builder to build his engines. With his 4” stroke at 10k rpm its super hard on a block. Plus he had one of the first ritter blocks and the problem was identified and fixed. He runs an R block now and is very happy with the results. I dont think an R block would survive what I put my motor through. There are so many factors in getting an engine to survive in a high hp application, well actually high torque because thats what kills, that results will definitely vary. My stock block stuff was very conservative. Using boost to make the power instead of timing or the fine edge of air fuel ratio will keep an engine from detonating and that, in my opinion is the key to making a stock block live. Much less any engine. I don’t advocate using the stock block but it can be done with careful tuning. We know a lot more now than we did long ago. Greg Aliano was really a pioneer in this arena