Another great and timeless design by Matt Jefferies.
However, I can't concur with some posters that the head only holds the officers quarters while the crew quaters are located in the engineering hull.
In "The Trouble With Tribbles" Captain Koloth mentioned that quarters aboard a Klingon ship aren't comfortable and I believe the crew is accomodated in the head, too, having crammed in bunk beds and/or beds that are shared by more than one occupant.
I believe Klingon technology to be somewhat inferior and crude in comparison to Federation technology, thus a large engineering hull with little or no quarters but plenty of radiation and therefore (similar to USS Discovery
from "2001") some physical separation between the engineering components of this vessel and the living areas at the bow.
Does the Klingon Battlecruiser use matter-antimatter reactors?
The Star Trek TMP Blueprints
provided these specifications for the "new Enterprise Class" and the "Drell-4" (K'tinga):
Warp: Dilithium Energized Antimatter
Impulse: Subatomic Unified Energy
Warp: Dilithium Conversion
Impulse: Hydrogen Energy