We have a 77 row crop on the farm that we still use to rake hay and haul wood.I have come across another engine that I would like to rebuild to have as a spare for the tractor.I noticed in alot of the farm parts catalogs that they list the same rebuild kits for the 77,super 77,770, and 1550.Did all these tractors use the same coponets?If so how did they increase power?Thanks for any help you might have.