The 1959 150 thru 1965 E models used the same early gear. 1966 150F thru 1970 150K used flat gear, but it is not interchangeable with the early models because of the mounting difference. Same with axles, same model range... different bolt pattern.
Did you Google 0441158-1, Gordon? There seems to be a few used early axles on the market. They fit 1959-1965 150's, early 172's, 175's, and 180's. P/n 1441003-1 is the heavy duty axle for early 180's and should also work with your gear and 6.00x6 wheels.
