470 to 120 swap

[Rranger]

I have a complete 120hp mercruiser setup prop to front engine pulley installed in a boat now. Have a chance for a better boat with a blown 470. If I completely strip the 470 down to the bare transom will there be any issues besides front motor mounts? Or is there more potential problems? I realize less speed with the 120 but it will get me to where I want to go.

 

[Bondo]

I have a complete 120hp mercruiser setup prop to front engine pulley installed in a boat now. Have a chance for a better boat with a blown 470. If I completely strip the 470 down to the bare transom will there be any issues besides front motor mounts? Or is there more potential problems? I realize less speed with the 120 but it will get me to where I want to go.

Ayuh,...... Should be a plug, 'n play,.....

 

[matt167]

If the donor boat is older than mid 70s the transom cutout is slightly smaller. But very doable if you have 2 complete boats

 

[Rranger]

I have a complete 120hp mercruiser setup prop to front engine pulley installed in a boat now. Have a chance for a better boat with a blown 470. If I completely strip the 470 down to the bare transom will there be any issues besides front motor mounts? Or is there more potential problems? I realize less speed with the 120 but it will get me to where I want to go.

Thank you matt167. Been awhile since I seen u on here Bondo I have great respect for your opinions. Thank you.

 

[stonyloam]

470, blown, how? If it’s just the head gasket, just replace the hg, five or six hour job. Problem is merc hg is NLA, and sierra is crap, so I went with a cometc 0.040 gasket for a 460 ford, kind of expensive, but works great. Just an alternative. Good luck.

 

[nola mike]

470, blown, how? If it’s just the head gasket, just replace the hg, five or six hour job. Problem is merc hg is NLA, and sierra is crap, so I went with a cometc 0.040 gasket for a 460 ford, kind of expensive, but works great. Just an alternative. Good luck.

Hey, Terry!
I used a Sierra HG in 2011 that was still fine in 2020 when I pulled the engine...

 

[stonyloam]

Hey Mike, yeah I got a sierra hg, did not like it compared to the NLA OEM, so went with a high tech one, so far so good. I’m getting too old and the head is too heavy to fo with.