You're switching from Metric to imperial. The instantaneous thrust would be Newtons, and the total impulse would be Newton seconds.  Lbf can be used to measure thrust yes, but I misread your sentence initially since lbf can mean both "pounds force" and (much much much much more commonly) "pound-feet" which is used to measure torque.

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due to the high torque generated.....(record set at 127,900 lbf of thrust)

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  My brain put the word torque at the end of that sentence for some reason

However, the moral of the story is that it's bad etiquette to switch from pound force to Newtons.

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That's not really a relevant comparison since the GE90 is a turbine jet engine and the Saturn 5 is a liquid fueled rocket. Completely different mechanisms of thrust generation. Plus the number he quoted was lbf of torque, not Newton Seconds of thrust.

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and the english unit of torque is pound-foot, but the more common terminology is foot-pound, abbreviated lb-ft and ft-lb, respectively.

Also I apologize for mentioning torque followed by the thrust capabilities, that was a really confusing sentence now that I think about it