decodeing 273 from 1964 plymouth

Recently purchased an engine and transmission from a 1964 plymouth valiant, its a 273 4 barrel, with what i believe to be a 4 speed. im having a hard time decodeing the numbers from engine and transmission, the numbers i have gotten from the engine so far are 2806030-273-6. that is from the drivers side of the engine block behind the exhaust manifold. im trying to figure out what transmission i have, the only numbers i have found so far are, c-85639u which was on the passenger side of the transmission and c-95858-0 on the tail shaft, also on the passenger side, these are the only numbers i could find. any help would be greatly appreciated. i did the best i could to read the numbers considering the engine/transmission have been stored outside for the past 20 years.