Should make a note here, after late 1973, the 440 began using the cast crank, low compression came in in 1972, the blocks from 1976 and on were very thin wall and Chrysler recommended no more than .020 on the overbore. I have heard of guys boring beyond the .020 but in my opinion would be risky. The best blocks were from 68 to 72, they also had an extra rib along the upper side of each block to prevent a cracking problem, some earlier blocks had.