Originally posted by jinx-mitchell
So it relies on the crank since all of the B18 blocks are pretty much the same size?
Yes. Rod/Stroke ratio is the ratio of the center-to-center length of the rods to the overall length of the stroke.
B16A and B17A blocks can swap crank/rod combos.
B16B and B18* blocks can swap crank/rod combos.
You can't swap between B16A pattern and B18* pattern blocks because the B18*'s deck is about 9mm taller.