There are no dumb questions. You were asking what is TALL speed but I feel you made a typo and probably were asking what is STALL speed. Stall speed is the RPM dependent on the type of torque convertor you have on your car that lets you launch and leave the line at a certain higher RPM level. See for instance, a 2800 stall speed convertor would allow 2800 RPM lanches off the line. I'm sure others more knowledgeable than me can chime in and give a more detailed mechanical explanation. Now if you're asking what is TALL speed then I can't really help?