4.000" - 4.060" Bore Piston Oil Ring Rail Spacer Support (0.020" Thick) Whether you're rebuilding a stock

Whether you're rebuilding a stock engine or changing to valve springs that have more seat pressure

Fits big block Chevy rectangular port cylinder heads on standard deck blocks

the least runout

making them ideal for withstanding the rigors of any demanding environment

The internal components are made from EN36 material as used in racing

4.000" - 4.060" Bore Piston Oil Ring Rail Spacer Support (0.020" Thick) Whether you're rebuilding a stockThese Speedmaster piston oil ring spacers are used in applications where the piston oil ring groove intersects the pinhole. Speedmaster piston oil ring spacers are manufactured from spring steel and install against the bottom sill of the oil ring groove. Available in different bore diameters to suit your specific engine's needs, the Speedmaster piston oil ring spacers will keep your pistons working smoothly throughout the entire operating range.