Possible to go without page headers?

I'm writing an index access method with its own unique file format. It
involves storing large blobs that break across pages.

The file format itself doesn't need or use page headers. There's no need
for a checksum or to manage free space within the page.

Can I treat pages as just a flat, open 8k buffer and fill them with
arbitrary data?

The reason I ask is that I see some reference to an LSN, used to determine
when to dump a dirty buffer to disk, and don't know whether that is
actually required. I plan to write a large number of pages all at once and
I'm not yet quite sure how WAL logging will work. I also see some
suggestion that the vacuum process uses page headers, but I haven't quite
figured that out either.