I remember having taken some pounding for suggesting that Reliant
's roll-bar pod might contain the antimatter for warp drive.
I just accidentally found an early design proposal for the Reliant
Bearing in mind that the Official TMP Blueprints
identified the front structures of the nacelles as "space-energy/matter sinks (acquisition)", i.e. intakes for space hydrogen aka matter reactants for M/AM annihilation, I'd say my idea wasn't that farfetched.
Matter comes in from the top, antimatter from the pods below.