Chrysler lower unit swap

[scotiany]

I have a 1970 Chrysler 55 model 554ha. Just bought Chrysler 55 model 559hd(1972?). The 72 is a long shaft. The 70 is a short shaft. The boat requires a short shaft-15 in. Is it going to be possible to swap the lower units. My main objective is to get the 72 model installed on the boat. I also bought a 35 Chrysler with a good lower unit. Will that lower unit work with the other two.

 

[norman158]

Re: Chrysler lower unit swap

the lower units should interchange even the 35hp the differance will be in (A) waterpump pickup location (some of the 35 and 45 hp chryslers had this behind the prop)(B)drive shaft (short and long)(C)water pump tube (short and long)(D)shifter shaft (short and long) hope this helps

 

[scotiany]

Re: Chrysler lower unit swap

Thanks for the info Norman158 . I've removed the lower unit and motor leg. from the 1970 model. I have also removed the lower unit from the 1972 model. I noticed on the 72 upper gearcase housing that there are 4 holes drilled(or cast) adjacent to the water pump on each side. They are not there on the 1970 upper gearcase housing. Do you think this is anything to be concerned about. Everything else(motor leg) seems to fit OK.

 

[norman158]

Re: Chrysler lower unit swap

You got my curiosity up so I went and looked at an old L/U that I have. It has a spot for the extra holes you mentioned but they're not drilled. Just little indents in the housing.I don't have a clue what they're for but I don't think you'll have any problems.

 

[landlock]

Sorry didn't mean to post yesterday in this forum.
Good luck with the L/u swap!:redface: