Direct Fit Aftermarket Performance Part
2023 Version with updated flow improvements. Flow Bench Tested and Dyno Tested!
The Cylinder Volume and Crankcase Volume Ratio have been thoroughly measured, analyzed and calculated for optimal performance.
New "Flow" Cuts increases port runner velocity which increases the effectiveness of the back plate function.
- More Power
- Better Throttle Response
- Faster Idle Drop Off-Power
O.S.-01: Fits the O.S. 21XZ Max Crankcase
O.S. 21XZ-B Engines
O.S.-02: Fits the O.S. B21 Crankcase
O.S. Speed Engines, Drake Engines, B2104, Ultimate, Etc...