37' prop shaft length

[letterman]

Mine was very long from the cutlass bearing to the prop. A mechanic wanted to know what the original factory length was and I can't tell him. Any ideas? .

 

[jimford2158]

On my 1974 37' the prop shaft is about a foot of length between the cutlass bearing and the prop. The transmission was swapped for a 72c which is longer than the original trans. You need to measure from the flange forward point to the cutlass bearing and then add about a foot for the total length of the shaft. Depending on the type of trans/engine(mine is a 4.108) and where the engine actually sits will determine the length. This would be easiest if the boat is out of the water. OR, go under the boat and clean the shaft(so that it will slide back into the boat) leave the prop connected, and undo the shaft at the transmission flange. Slide the shaft as far forward as it will go, if you can clear the trans, and you will see how much too long the shaft is, minus a couple inches for clearance on the outside once reconnected. I added a center bearing and a crossmember in the bilge to steady the shaft and a double carden u-joint and there is now no vibration. Although the shaft is still too long. I doubt if you will find any specs on the length of the shaft. Best thing is to just slide the prop forward to check clearance and then measure to the flange. In the picture the prop should be a lot closer toward the front of boat(shaft should be shorter) Good luck.