Difference between 250cui and 292cui

FreeBeeTony

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May 15, 2002
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I was reading my manual and was wondering what the difference was between my 165 Mercruiser IL6 which uses a 250cui GM block and a 200 Mercruiser IL6 which uses a 292 GM block.<br />The bore is the same but the stroke is ~0.5" larger.<br />Does the 292 use the same block as the 250 but different crank and connecting rods?<br />If so, I wish I knew that when I did the rebuild! Might have been an easy way to add the extra HP.<br />Is this right? Or is there more to it?<br />Would I just have to find a 292 crank and rods to convert this 165 into a 200?
 

b20

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Re: Difference between 250cui and 292cui

Hi Tony,block,pistons,rods and cam are different.probably a few others too,but i didn't look that far.
 

FreeBeeTony

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Re: Difference between 250cui and 292cui

Oh........... :( , I am learning about the term "stroked". I was just wondering.........guess it doesn't seem to feasable. Heard of using a 292 crank w/ V8 rods?
 

Bondo

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Re: Difference between 250cui and 292cui

I'm not cerntian about the in-line motors,<br />But with the SBCs, The Rods are All the Same Length......... 5.7"<br />With the exception of the 400cid which uses a 5.565".........<br /><br />I'm just Guessing here,<br />But I'll bet that the in-line 4s,+ 6s all use the same rods......<br /><br />Stroke is adjusted for at the Piston.....<br />The Pin is moved either up, or down the piston skirt.........<br /><br />I don't Actually Know, But I would think that your observation is Probably True......<br />If So, A Crank,+ Pistons would do it..........
 

Laddies

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Re: Difference between 250cui and 292cui

the 200 was a 4 barrel carb and a mercrusier II unit also
 

FreeBeeTony

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Re: Difference between 250cui and 292cui

Found another post here ...........am not having much luck finding anything else on the web.<br />Thought this would catch your attention bondo....<br />See the post regarding the external balancing of the crank? Seems like it might be alot of work!<br />I have a "spare" block in my basement...thought it might be a cool project.<br />What do you guys think? Or am I nuts.......... :)
 

rodbolt

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Sep 1, 2003
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Re: Difference between 250cui and 292cui

hello<br /> there are a lot of parts that interchange on the 250 and 292 and a lot that dont. years ago there were some racers that used the 292 cranks and heads and such. try to find and post about it on some of the chevy racing sites. the 292 has been about for years as has the 230 and the 250. I have seen some screaming six's in my time at the track. makes me wonder why they never tried the ford 300 CID six.
 
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