But "warp drive [antimatter] pods" could be located anywhere...
Granted there's a little wiggle room there, but not much. References to "warp drive nacelles
" and "warp drive pods"
as well as "anti-matter nacelles
" and "anti-matter pods"
yet still other references to "matter/anti-matter nacelles" and
pretty much show that the terms "nacelle" and "pod" refer to the same thing and are interchangeable.
In "The Apple" Scotty refers to the antimatter pods
being inert and in reply to this, Kirk tells him to jettison the nacelles
if possible; so at the very least, the pods are in
the nacelles, but more likely they are
Also, the fact that the pods are called warp drive pods
in “The Doomsday Machine” and then “Metamorphosis” indicates that that the Pods
(on the shuttlecraft) are related to maneuvering, strongly implies that they are synonymous with the nacelles/propulsion units.
Perhaps... close to the (photon torpedo launcher?) antimatter tanks on Deck 11 in "Errand of Mercy"?
What dialogue establishes antimatter tanks on Deck 11?