My turbo choose changed when I had issues with bolt threads on my small turbo. I kept looking at the AC190 turbo thinking how easy the installation would be so I decided to give it a try thinking if performance was poor on the 770 I could always put it on the 870. This was a fairly straight forward project using that turbo, Bolted up to the manifold and exhaust will exit the original location using the 190 elbow and spacer. I had to redo the factory oil drain pipe but it bolted up. Inlet and outlet air pipes had to be fabricated but there was room to leave the air filter and hood precleaner pipe exactly as they were. I am pleased the way this went together and it works well. Dynoed before and we had a very smoky 65 hp, so someone had messed with the fuel before . After turbo it has 91 hp with about one third of the exhaust smoke. I am very pleased with the numbers and plan on leaving it as is. The tractor will be used for recreation tillage and will not be a main work horse. It always seemed so sluggish compared to the 870 , but now the tables might have turned . Rod.