U never mentioned the engine was old and tired and that u were gonna do a refresh/rebuild. U said Jim gave u the only answer. If u think u can do 600/600 on pennies ur sadly mistaken. It takes precision machine work, not the run of the mill overhaul. It won’t be a very drivable street car at 600/600. Kim
The engine being tired has nothing to do with the power capabilities of the heads. I never said I was going to build a 600 hp engine. So far, I've had 2 clear opinions on the original question. If you can't answer the original question, move on.