The factory rated horsepowers were as follows: 6620 belt drive - non-turbo 120 hp, 6620 hydro - turbo 145 hp, 7720 belt drive - turbo 145 hp, 7720 hydro - turbo 190 hp, and the 8820 hydro I believe was rated at 225 horsepower. I'm not sure, but I don't think Deere increased the horsepowers when they brought out the T2's. All combines had the 466 CID engines. This is according to the sales literature which I still have.