Need help understanding GM Inline 6

BryanF

Cadet
Joined
Jul 1, 2003
Messages
25
Hello, Maybe someone can help me understand this better. I'm trying to figure out 1st what i really have as engine/outdrive goes. I have a 1969 24' Formula Thunderbird. <br />Could someone explain to me the difference in inline 6's (i.e. 160,165)and sterndrive hp match ups.<br />The mercruiser sterndrive has a sticker the says 165hp. (What model it is a whole other question. :D ) <br />The Engine is a GM "Inline 6". There is a sticker on the valve cover that says 160hp. I believe it is a 250cid. Can a 250cid be a 160 or a 165hp? <br />Should the engine HP and sterndrive HP read the same? <br />I've heard of a 292cid Inline 6. (are these used in boats also?<br /><br />Thank you for the help<br />Bryan
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: Need help understanding GM Inline 6

Your engine is a 250...when ordering parts for the engine...Tell the dealer its the 160hp. When ordering parts for the outdrive..tell the dealer its the 165hp.<br /><br />I think this only happend for a couple years in the 70's.<br /><br />TMD
 

metwrench

Petty Officer 3rd Class
Joined
Aug 16, 2003
Messages
86
Re: Need help understanding GM Inline 6

The CID is Cubic Inch Displacement, This is the actual Size of the engine Internally speaking. The size of the Cylinders, Stroke and Number of Cylinders being 6 of course. Dont confuse this with Horsepower ( Hp ) Horse power is the amount of actual Power the Engine produces, Has Nothing to do with SIZE, has everything to do with how well the engine is producing power. The " In line" term comes from the fact the Cylinders are all in line with each other, Configured. Some different Configures would be: V-6 ( Cylinders are in a V design with 3 per side ) Slant 6 * cylinders are at a Tilt when engine is Straight up) V-8, V-12, Straight 8. Most of the other configures are Automotive Use.<br /><br />Hope this helps you<br /><br />John
 

BryanF

Cadet
Joined
Jul 1, 2003
Messages
25
Re: Need help understanding GM Inline 6

Thank you for the replies.<br />Is there a inline 6 250 that is 165hp? <br />Are there other CID for a inline 6 marine use?<br />Thank,<br />Bryan
 

metwrench

Petty Officer 3rd Class
Joined
Aug 16, 2003
Messages
86
Re: Need help understanding GM Inline 6

Sorry Brain, I cant answer that question..I mostly do Automotive Stuff not Marine. But someone on here should know that question.
 

The Marine Doctor

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Joined
Jul 25, 2003
Messages
2,177
Re: Need help understanding GM Inline 6

The very first 250's that were used in boats were 160hp.<br /><br />A few years later the 165hp was adopted as the norm for the inline 6 250.<br /><br />TMD
 

BryanF

Cadet
Joined
Jul 1, 2003
Messages
25
Re: Need help understanding GM Inline 6

Thanks guys,<br />So then chances are that this is the original 160 hp motor, being the boat is a '69, may have been rebuilt if anything!? <br />The actual year of the engine block should be stamped on the block somewhere, right!? <br /><br />Is there a newer version of the GM inline 6 (w/o points or maybe fuel injected) that could "drop in" w/ little structual mod., into the old 160's place?<br /><br />Thanks,<br />Bryan
 

FreeBeeTony

Captain
Joined
May 15, 2002
Messages
3,991
Re: Need help understanding GM Inline 6

I just finished rebuilding a '67 Mercruiser 160 and converted it to electronic ignition. I have been told that this is a great engine for marine use. Parts are available and easy to get. If the block is good I would consider rebuilding your self, it's very easy to work on.
 

BryanF

Cadet
Joined
Jul 1, 2003
Messages
25
Re: Need help understanding GM Inline 6

Thanks FreeBeeTony,<br />When you converted your 160 ignition, was it "Marine" grade or just a Automotive electronic ignition?<br />Is there even such a thing/difference?<br /><br />Thanks,<br />Bryan
 

pecothern

Seaman Apprentice
Joined
Aug 13, 2003
Messages
45
Re: Need help understanding GM Inline 6

Careful...... Marine distributors have spark arrestors. They look like screen wire over any vent holes. Lots of sparking going on in the distributor. Potential for fuel vapor in engine compartment...BBOOOMMM!!!
 

FreeBeeTony

Captain
Joined
May 15, 2002
Messages
3,991
Re: Need help understanding GM Inline 6

I used the Petronix Ignitor II conversion kit with the original distributor.
 
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