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Discussion Starter #1
I've been looking around the web and all of the LSx builds for a 4.00" and 4.100" stroke all call for a 6.125" connecting rod. Why not a 6.200" con rod ?? Are they afraid that the piston used will be too short and not durable??

I did see that Lough Engine Service of Oak Ridge, Missouri and CC Performance Parts of St. Helens, OR does sell 416 ci and 427 ci LS3 stroker builds with the 6.200" rods, but nowhere else that I have seen.

Is it true that the LS3/L92 block has sleeves long enough to accomodate the 4.100" stroker crank without poking the pistons out of zeroed deck where the LQ9/LQ4 block is does not???. So can I build a 427 ci shortblock that can be used for a daily driver with occasional road race and autocross use if use the LS3/L92 block instead of the LQ9/LQ4 iron block??? Can it be as durable as the using the iron block?? Let's say a good 100,000 mile motor?
 

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yup not enough meat on the piston, ring packs to close to the crown etc. it might work of for an na build. but personally Id want the stronger piston.
 

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schwanke engines will build you a iron 427 I could not comment on reliability. contact them, still those few extra cubes are not worth the trade off IMO.
 

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The pin is in the oil control ring with a 6.125

Just because someone is doing it dosn't make it a good idea. LOL
 

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Discussion Starter #5
yup not enough meat on the piston, ring packs to close to the crown etc. it might work of for an na build. but personally Id want the stronger piston.
Good point. In fact CC Performance on their website specified that their LS3 427 build is NA only. Which is fine by me since I am not looking to do any power adders. If is was going forced induction I would have gone with a smaller displacement. The same strategy the GM employed in ZO6 Vette vs ZR1 Vette.

The motor I'm contemplating is for a '95 Caprice B-Body so I got over two tons to motivate. So I looking the the biggest but at the time most reliable and longest lasting NA LSx build.
 

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The motor I'm contemplating is for a '95 Caprice B-Body so I got over two tons to motivate. So I looking the the biggest but at the time most reliable and longest lasting NA LSx build.[/QUOTE]

There is reason most won't go past a 4" stroke on Gm blocks. I would not do it even it was na only, you don't want to end up with a oil burner. get good heads and don't go nuts on the cam and you will have plenty torque. You used the word long lasting and reliable. :smt102
 

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Nowadays many builders believe a longer rod is a waste, within reason. I'm no pro at this, but I would trade a little rod length for a little taller piston in most cases.
 

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I remember there being a lot more academic sounding debates about rod length. I think the conventional wisdom today is that whatever rod lets you run the right piston is the way to go. Obviously you can run a longer rod in lower stroke application.
 

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Not an expert by any means. Seemed like in my small block Chevy days, everyone was pushing for longer rods. Replace the short rod in a 400 (5.562??) with a 5.7. If you could afford to run a 6" rod, do it. I don't hear much about rod length, or longer rods in the LS world. Not much talk about rod ratio.
 

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If it's a stock stroke build and N/A, I prefer to use a 6.200" rod. Stock stroke and moderate N2O or boost I use 6.170 - 6.190 depending on how much--if any--street.
 

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Why not use stock crank a 6.300 rod with a 4" stroker piston... Plenty of meat on the piston then...
 

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What size bore are you looking at??? 4.065(LS3/L92 size)??? 4.070?? 4.080??

I was looking a 427 ci LS3 based stroker.
Bore size has no baring on the compression height of the piston.

An .043" ring pack isn't in your best interest for what you're trying to do. Using a 6.300" rod, you would need to do so for piston integrity.
 

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so if I have 6.200 rods in My 383 I have a potential problem? Its never been started is now the time to get new rods and pistons and rebalance?
 

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so if I have 6.200 rods in My 383 I have a potential problem? Its never been started is now the time to get new rods and pistons and rebalance?
N/A, boost, or N2O?
 

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Yet. You are far more likely to snap a ring land thani if you had a stock stroke crank and a 6.1 rod.
In general, this is very true, but it does however depend on the ring pack, piston design, ring land(s) locations and piston pin location.
 
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