Technical Specs:Alloy: Hypereutectic 390
Bore: 4.030''
Crankshaft Stroke: 3.250''
Connecting Rod Length: 5.700''
Deck Height: 9.025''
Compression Height: 1.678''
Pin Size: 0.9272''
Pin Location: Centered
Flat Top: -7cc 2 Symmetrical Valve Reliefs
Intake Valve Relief: 0.280'' Depth / 2.168'' Diameter
Exhaust Valve Relief: 0.280'' Depth / 2.168'' Diameter
Top Landing Height: 0.275''
Ring Grooves: 5/64'' Top; 5/64'' Middle; 3/16'' Bottom
Gram Weight: 569/145
Compression Ratio: 10.3:1 w/58cc Heads; 9.8:1 w/62cc Heads; 9.6:1 w/64cc; 8.4:1 w/76cc Heads