D16Y1 & D16Y8 CR difference

[gambate]

i have been playing with the Compression Calculator (http://www.knology.net/~jediklc/D.htm) for D series

Wondering if the D16Y1 and D16Y8 parts is interchangable.
if it could, what combination would give highest compression?

What is the Piston-to-Deck Height?
how do i determine which 1 to select for this option for
1. y1 block and piston with y8 head
2. y1 block and y8 head and piston

can the ZC piston be used in Y1 block?

AFAIK the d16y1 is same as USDM d16z6

Thanks is advance