Add to Favorite Sellers. Quality Aftermarket Tachometer Fits International Harvester IH Farmall 544, 656 Row-Crop w/ Gear Drive & w/ T. Gas, diesel Tractors Specifications Has single light hole in rear. 4.240″ outer housing diameter 2.250″ housing length Replacement Numbers 103153A1, 389973R91, 401841R91. We recommend verifying the proper fit for your application with a parts catalog or other reference documents. All aftermarket items have been hand selected by our team and are continuously monitored by a quality control department. Should a craftsmanship or fitment concern be identified, JJAgParts will be sure to work with our customers to stand behind our products. Be sure to check out our other listings for great aftermarket and NOS items! Don’t forget to leave us feedback and we will be sure to do the same! . Thank you for this opportunity to earn your business! Thank you for looking! We appreciate the opportunity to earn your business. Feel free to ask any questions you may have.