Originally Posted by cepx111
Correction.....
The taller counterweights would hit the bottom of the piston skirts, not the rod.
You can use a 6 inch rod on a 5.7 crank but you can't use a 5.7 rod on a crank designed for a 6 inch rod.
You get the prize for the correct answer!!! 8) 8) 8)
The counterweights for a 6" rod crank will hit the skirts if a 5.7 rod is used, however you can run 6" rods on a 5.7 rod counterweight. The reason for two different? Larger counterweights are easier to balance, less heavy metal. Larger strokes make this even worse, limiting the counterweight size. The 3.875 crank would need to have the counterweights turned down, then balanced with more heavy metal to use 5.7 rods.