Perhaps inevitably, Scott has a better copy of the second image (at least):
The 1957 Convair document
Characteristics of Tactical, Strategic and Research Missiles gives three warheads for the 'B-58 Pod': one of 2,800 lb, one of 7,000 lb, and one of 20,000 lb.
apps.dtic.mil
Those correspond fairly naturally to the second-generation thermonuclear W27, W39, and W36 warheads respectively. Which I identified back in 2014, but we can do better.
However, we know that the MB-1 (and presumably the corresponding MA-1) pods carried the W39. Scaling pixels implies that the other two carried proportionately larger warheads:
- MA-2 & MB-2 - Approximately 38" x 120" - perhaps corresponding to the W46, which is known to have been planned for the B-58.
- MA-3 & MB-3 - Approximately 49" x 140" - perhaps corresponding to the W41.
My guess is that as development progressed, it was seen as inefficient to use the B-58 to deliver a single Class D weapon, and the W27 warhead was dropped. The MB-1 with a W39 was the initial service model, and it was expected to replace this with the -2 and -3 pods carrying higher-yield W46 and W41 warheads.
With limited service of the B-58, and the fuel leak issues, none of the other pods were developed. The BLU-2 Two-Component Pod did, however, use the W53, which evolved from the original W46.
