You're confusing work and torque. Work is force x distance. Torque is the moment of force...force x length of lever. It's confusing because Torque is sometimes measured in lbft, while work is sometimes measured in ftlbs.

Yes, you could stall your motor by standing on a foot long bar. Please don't verify by experiment. The way this is actually measured is by attaching the crankshaft to a turbine where water pressure is applied until the engine stalls. The reason this is counterintuitive is that other stuff...power. Your engine can move that 150 pounds a long way in a fraction of a second. The end of that lever would be moving at almost 2 miles a minute. It would tear your arm off before you could grab on, unless you were also spinning at 2500 rpm.