The '68-71 318's were mostly cast cranks too. Some truck and other industrial engines still used forged ones, even after '72, but not all. I mainly found them in manual trans applications. All the '67 and earlier small blocks had forged cranks. In swapping around small block internally balanced cranks between engine years and sizes, always check the converter hole diameter, pilot bushing hole if it's a manual trans application, and rebalance the recipricatiing assy as the bob weights are all different. Use the balancer that matches the year of your pulleys.