470 to I6

hadaveha

Petty Officer 1st Class
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Mar 17, 2009
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389
Guys this may be stupid question, But a freind of mine has a great running mercruiser Inline 6 165 . I have a 470 inline 4 if you was to look at swapping roughly how much more foward space would I need. The 470 does have the alternator conversion on it so it longer than the stock 470. Thank You all for taking time with a dummy like me
 

Bondo

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Re: 470 to I6

Ayuh,.... I'd guesstimate, 'bout a foot,...
 

stonyloam

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Mar 13, 2009
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Re: 470 to I6

Just a guess, but seems like it would be at least 8-10 inches longer probably more. What is wrong with the 470?
 
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hadaveha

Petty Officer 1st Class
Joined
Mar 17, 2009
Messages
389
Re: 470 to I6

Im working on the 470 now, I have a extra 470, his uncle passed and left him this boat, the inside is rotten but the inline 6 looks like brand new, his aunt said it may have 150 hrs on it he bought it new. He wanted my spare 470 for a racecar praject he was working on. I just thought if it would fit it would be a tune up and drop in. and I grew up working on these strt 6's most of us 70's kids did, I know my way around one of these very well. but I dont think I have a foot to spare under the cover
 

hadaveha

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Mar 17, 2009
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389
Re: 470 to I6

IM sorry you ask about the 470, its just the norms, cam seals, head gasket, leak somewhere in the exhaust I have to find.
 

stonyloam

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5,827
Re: 470 to I6

Yeah standard stuff LOL. Exhaust leak, behind the engine? Look for a rusted out thermactor plug on the back of the head. It looks like a small "freeze plug". There is one on the front of the head too. If that is it, try your local Ford dealer, for a thermactor plug for a Ford 460 head. The rest, use a OEM Mercruiser head gasket (seals better). You might consider having hardened exhaust seats for the head. Probably a lot easier to fix the 470 than shoehorn the I6 in. Good luck.
 

boat_chick

Cadet
Joined
May 3, 2010
Messages
7
Re: 470 to I6

In a prior post, it was suggested to use an OEM 460 automotive head gasket. I dont recommend it, having done that myself. The 470 block has tiny coolant passages between the cylinders. The marine gasket is specially gusseted for these. The automotive one blew out between the cylinders and I ended up blowing all my coolant out from combustion pressure. Had to replace it again with the one designed for this engine. Just a opinion of my experience. My 470 has been a wonderful, expensive, fun, sad, maddening, confusing and ultimately satisfying learning experience. Good luck!
 

hadaveha

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Mar 17, 2009
Messages
389
Re: 470 to I6

this im sure this is a brain dead question, where I am at I don't really have a mercruiser dealer very close so most everything I get I order online, so how do I know if Im getting the oem head gasket
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: 470 to I6

this im sure this is a brain dead question, where I am at I don't really have a mercruiser dealer very close so most everything I get I order online, so how do I know if Im getting the oem head gasket

you buy it from a mercruiser dealer, many dealers sell online
 
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