Thomas Harris, Laurel, MD , 1968 Plymouth Barracuda 447
When the mains of a 440 crank are cut down to install it in a low deck (383) block and the counter weights make contact with the underside of the block, what is the cure? Do you mill the underside of the block or do you trim the counter weights?
Tom, the interference is almost always at the bottom of the barrels, you simply grind each (die grinder) as required, until there’s at least 0.030 – 0.045″ clearance. Typically there’s also interference at the rods, too, same fix there.
However, if you’re using lighter than stock rods and / or pistons, you may find that the counterweights can indeed be cut down some and still be easily internally balanced. If that’s the case, obviously do this before the hand clearancing operation. This mod also reduces windage a little, so it’s win-win.