MBM-MC1312A-Universal Aluminum Master Cylinder Ultra Light Weight GM Universal 1" Bore; 3/8" Ports on Both Sides; Master Cylinder has a piston adaptor that will allow for power or manual applications. (Note: if you are running Drum/Drum you will also need a metering valve PVM)1" stainless steel sleeved boreUnpolished aluminumHeight from center line to the top most point on the wire bail is 3.5"3/8"-24 inverted flare ports on each sideIncludes plugs for the side not usedDeep piston with "bullet" design for manual or power brakes