We use the finest high purity 4340 aircraft quality alloy and forge it by the experts in American crankshaft forgings, Louisville Forge in Kentucky. Then they're shipped to the leader in high performance crankshaft machining, Callies Performance Products, where they are machined to the highest specifications, with roundness within 60 millionths and taper being held to within . 0003" on all rod and main diameters. All journals have . 125" Tru-Form fillet radii. 1" Angalite lightening holes in all rod throws. Callies Perma-Toughs these cranks to a depth of . 080". This produces a wear layer that remains intact even if reground . 060" under (other cranks have a hardness depth as little as . 003"). Journals are micro-finished to 5 microns or better.Pit Stop USA offers Howards Pro Series 4340 Forged Crankshaft - SB Chevy - 350 Main - 3.875 Stroke - 6.000 Rod 353860 at low everyday prices. Be sure to check out all of our products from Howards Cams including Howards Racing Components Forged Crankshafts - Small Block Chevy.