exactly that:

Can a d16y8 header work on a d16z6?

and if yes, what are the differences?

 

check with someone that manufactures or sells them to be 100% sure. but, i would be willing to bet it would work. d series parts are almost always compatible with one another. i bolted up a 97 d15 tranny to a 91 d15 block no problems. only problems i encountered were mounts and the clutch system. anyway, the bolt patern for the two headers in question should be exactly the same.