360 390 401 AMC stroker crankshaft billet steel 4 inch stroke. Stock AMC main journal sizes, Rod Journal Size is 2.100 small block chevy diameter. Rear Flange 6 Bolt AMC 1971 and earlier style. If you want to use a 1972 or later style flexplate / flywheel a concentric adapter will be required.
Old K1 part number: 390-4000LB6B New number: 002AAD400