Will it blend:

This needs to meet that. How hard can it be?

Not that hard, as it turns out:

M'mmmmmmm, homebrew:

The flats across the manifold are to stop the flange (heh, flange) curling up on itself, thus stopping it from sealing.
Snuggly in there:

The engine that should have been there all along:

No airbox is available, hence the cone-age.
As we're keen we did a little further mod:
