Torque converter stall speed is governed by the amount of torque the engine has. The same torque converter behind a Chevrolet Vega 4 cylinder will stall at relative low rpm, take the same Vega converter and put it behind a 454, it will stall at much higher rpm. The vega converter was to go to back in the day just for this purpose. The converters that are sold as "3000 stall speed " will only do that if the engine has the power, don't expect a stock 350 to stall up that high, unless the converter is made with junk parts. My racing converter would stall about 2700 rpm with foot brake in my '67 GTO, same converter in my dad's 1000 lb heavier wagon would stall about 3100 rpm, better brakes, more weight, and higher torque. The really good converters, $800 + , will work at relative low rpm for everyday driving, but still stall up when asked to. The cheap ones, slip most of the time.
The tight converters, where stall speed is low ( 1600 - 1800 rpm ) are much better on fuel mileage, less slip so more of the power being made is being used. The lock-up converter was a way to gain more mileage and mimic the manual transmission clutch, full locked-up with zero slippage.
To many words ?
