If they're talking about a generator that's expected to run at its peak power all the time, then I'd expect it to be heavier than an automotive engine that only

If they're talking about a generator that's expected to run at its peak power all the time, then I'd expect it to be heavier than an automotive engine that only hits peak power intermittently. and 40 hp is 29.8kW. they're both measures of power. you don't need to know the torque to make the conversion.