Hi prezz...<br /><br />Check that the drive shaft splines are the same and the bolt holes will match to the midsection. Usually lower units from this time frame can be interchanged with no problems.
The only 25hp that will interchange with the 1956 30 is the 1955 25hp (Evinrude model 25018 or 25019 or Johnson model RD-17). 1954 and prior had a different bolt pattern and different water uptake method...<br />- Scott
