Speed Pro Hypereutectic Pistons w/ Moly Rings Kit Small Block Chevy 327 Size: 0.40 Over Bore Bore 4.040" Piston Style Flat Top with Two Valve Reliefs Piston Material Hypereutectic Aluminum Compression Distance 1.675" Piston Head Volume +5.00cc Wrist Pin Style Press-Fit or Floating Pin Diameter 0.927" Piston Ring Thickness 5/64" x 5/64" x 3/16"