What are the differences between D-series short blocks? I know they have different pistons but what about the rods and crankshaft?

 

blocks are different too... as i have both sitting on my garage floor the z6 block takes a different water pump thn the non vtec blocks (like the d15b7 block i have). There are also more slight differences in block. Not sure measurement wise.

As for the rod lengths and stroke lengths i had a webpage i will try to find a link to it..

 

I've read that the D16y8 has an oiling problem with the bearings. Does the D16y7 or y5 have this same problem?