Will the crankshaft from a 366 Chevy engine fit a 396 Chevy engine?

No, the crankshaft from a 366 Chevy engine will not fit a 396 Chevy engine. While both engines are part of the Chevrolet big block family, they have different specifications, including stroke length and journal sizes. The 396 typically has a longer stroke and different mounting characteristics, making them incompatible without significant modifications. Always consult specific engine documentation or a professional for precise compatibility details.