Re: 8 million pounds thrust
four RS-52 motors providing two million pounds of thrust, “working in conjunction with a pair of solid rocket boosters to produce up to eight million pounds of thrust”.
Presumably that's 4 motors producing a total of 2m lbf, otherwise the solid boosters wouldn't be adding much. In which case why not just use 3 solid boosters alone?
A Saturn V managed 8m lbf with 5 F1s and no boosters. Almost 60 years ago :(