This is our 5 Bolt S10 NP231C to 6 Bolt Round Adapter. Machined from 3/8" Steel to allow Maximum Spline Engagement, Strength and Durability. Our Adapters and Precision CNC Machined for Accurate Bore Alignment. This Adapter is Designed to Convert the 5 bolt NP231C to the Standard GM 6 Bolt Round Pattern. This allows the NP231 to the TH350/700R4/4L60E Transmission or our BlackBox/EcoBox Underdrive.
**The NP231C Transfer Case from the S10 came with two different Pilot Bore sizes 4.125" and 4.89" please verify your transfer case before ordering.**