V8 swap from 165 hp straight 6 omc

metalwizard

Chief Petty Officer
Joined
Sep 13, 2010
Messages
411
so. I have water in my oil on my 73 omc 165 hp straight 6

I have been trying to locate a suitable replacement, with so so luck.

It just came to me that I have a 400 small block in good running order.

Other than the obvious stuff (distributor, wiring exhaust etc) is that a swap that could happen without out a HUGE drive issue?

My drive is an OMC stringer. I am not sure if it 400 or 800. BUT if I had the forward motor mount would it work? or is there just to many things to change?

I am an ex Chevy line tech so the standard stuff is easy. I just wondered if the bell housing flywheel would work and what I would need for exhaust?

I cannot read the tag in the boat saying maximum HP etc so it would be my best guess on that. it is a 18 foot boat, and I think they did offer them with a v8.

anyways has anyone done this swap? what do I have to think about. or should I not even think about it?

thank for the input
 

semo549

Petty Officer 2nd Class
Joined
Jun 18, 2009
Messages
104
Re: V8 swap from 165 hp straight 6 omc

If your drive was made for an 165, I'm sure you would have the wrong drive ratio. I also highly doubt it would handle the extra ponies of the 400ci
 

metalwizard

Chief Petty Officer
Joined
Sep 13, 2010
Messages
411
Re: V8 swap from 165 hp straight 6 omc

thanks. I kind of figured. but wanted to know for sure.
 

dan t.

Lieutenant Junior Grade
Joined
Feb 28, 2008
Messages
1,131
Re: V8 swap from 165 hp straight 6 omc

If it is an 800 drive it will take the power no problem. The V8 ratio is 1.5 ,the 6cyl not so sure.If it is a 400 drive forget it , it wont take the power.
 

86 century

Ensign
Joined
Sep 8, 2009
Messages
986
Re: V8 swap from 165 hp straight 6 omc

The 400 are external balance so the flywheel wont fly. It will bolt on but she will shake your teeth out.
 

Bondo

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Staff member
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Apr 17, 2002
Messages
70,468
Re: V8 swap from 165 hp straight 6 omc

Other than the obvious stuff (distributor, wiring exhaust etc) is that a swap that could happen without out a HUGE drive issue?

Nope...
 
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