It is a Spicer Dana 60 sure grip with 3.55 gears (pretty low geared with my 3 speed 727). To give you an idea, I am turning 3000 RPM at 65MPH, 4000 at 85MPH, and 5000 at a 105MPH and almost 6000 at 120mph. So it is perfect for the quarter mile or jumping on it from 20-80mph if someone rolls up alongside of you and wants to "get up the speed limit quickly" :)
