LS SERIES CRANKSHAFTS BC performance crankshafts are CNC milled from 4340 non-twist forgings in a stroke range of 4.000" 4.125" and 4.250". Counterweight O.D. is designed for 6.100" to 6.125" length rod approx. 1875g bobweight. Fully CNC'd on 5-axis machining centers including oil holes for the best oiling possible. Includes 2 keyways on the snout (OEM is 1 keyway) for added keyway support in heavy duty applications gun-drilled down the center to lighten it up without compromising strength. For more information visit http://www.briancrower.com/makes/chevy/ls_cranks.shtml