GX390 +.200 Stroker Crankshaft. 2.720"(69mm) stroke with standard crank pin diameter. Machined in house from hardened 4340 Chromoly to the exact standard you have come to expect from ARC. Dual plane balanced to eliminate the need for the OEM counter balance system. Design for use with the ARC 6272 rod and the 27-3464 (88mm) piston. 1" PTO shaft. Some internal engine clearancing may be required. If using piston bigger than 90mm, re-balancing may be required.