Except that your math is wrong, guess you forgot your glasses. hp/lb... the R3300 series of engines had many ratings, but it also had cooling problems which was exasperated i the limited space of the B-29, the version 42WA which was originally to be used in the Hughes aircraft was rated for 3700 hp, and as much as 3,800 hp.
8 x 3,700 = 29,600 hp.
29,600 hp / 400,000 mw = 0.074 hp per pound,
slightly better than that of the B-29, which was 0.073.
Phil
