Looks to me like the freezing water syndrome. I'm almost sure that with pressure built up from exhaust you'd never get that amount to break a housing -- and the engine wouldn't even run. Perhaps heat buildup, and no pressure relief in the gear case you could split it, but most likely the pressure would sneak out the seals. I would bet that there is no geargrease in the lower unit, or very little. If El and Bills multihoured lower unit is a fit, I'd bolt it on after replacing the lower prop seal and the driveshaft seal and shift seal. I'd leave the rest of the unit together and put nice clean gear lube back in.
:shock: Best luck, Ron
