Add to Favorite Sellers. Muffler Fits International 666 686 706 766 806 826 856 Tractors 530578R4. Quality Aftermarket Muffler Fits International Harvester IH Farmall 666, 686, 706, 766, 826 Gas, LP; (706 w/ D310 German diesel); (806, 856 Gas, LP, Diesel) Tractors Specifications Black finish 3-1/4 inlet length 2-15/16 inlet inside diameter 23 shell length 8-1/4 outlet length 3 outlet outside diameter 34 overall length Replacement Numbers 530578R4. 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.