Boss 351 Cylinder Block Big Bore; 2.749 Inch Main Journal Diameter; Finished At 4.120 Inch Rough Bore/ 4.125 Inch Cylinder Bore; 9.5 Inch Deck Height; 4.250 Inch Maximum Stroke Recommended; 2 Bolt Main Caps On Journals 1 And 5 And Splayed 4 Bolt Main Caps On Journals 2/ 3/ 4; Not For Sale On Pollution Control Vehicles