LS7 427 vs 440 question
10-06-2009, 10:49 PM
#2
Is the 440 gonna be a 4.125 stroke x 4.125 bore? Some will say that stroke is too long for the LS7 block sleeves. But if the piston is built right it WILL be fine. My 427ci has the real old LS1 sleeves and it has a 4.125 stroke, and this thing is still fine after 7+ years.
But you'd be better off going with a resleeved LS2 440ci with the new 5.8" long Darton sleeves, alot more piston support.
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But you'd be better off going with a resleeved LS2 440ci with the new 5.8" long Darton sleeves, alot more piston support.
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10-07-2009, 02:32 PM
#6
I'm not saying a 4.125 stroke won;'t work in the older shorter sleeves....thats what I have, a 4.125 stroke in sleeves from 2001. I have over 124,000 miles on my 427ci and its great. Its does burn oil and I'm certain the cylinders are out of round, but 7+ years and its great.
I'm just saying, if he is starting fresh...he might as well do it right with the longer 5.8" long NEW Darton sleeves in a resleeved LS2. Much better than using an LS7.
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10-07-2009, 07:22 PM
#11
I just figured he was talking 4.125 bore for the 427ci. Then just use a 4.125 stroke and make a 440 instead.
But yeah, I like your's better because of the shorter stroke. Or even a 4.125 bore x 4.1 stroke (438ci...can still call it a 440).
When my new engine gets done, I'm gonna pull my 427ci out (4.125 stroke x 4.060 bore), I'm gonna have it freshend up and further bored out to 4.125 with new pistons to make a 441ci. Put it back together and then sell it as a newly rebuilt 441ci.....cheap.
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10-08-2009, 07:30 AM
#12
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Do they measure 'em differently? 5.8" is 5.8", either way. Not trying to argue, just don't understand. I have a LS7 block and don't see any reason not to go with the longer stroke...it's only .100 longer than factory which puts the pin .050 higher in the piston. Unless you absolutely can't spare the .050, there's no reason to go that way.
"Build it as big and bad as you can, or you'll get tired of getting your a$$ handed to you by the guy that does".
...Crusty Old Fart engine builder in my past
"Build it as big and bad as you can, or you'll get tired of getting your a$$ handed to you by the guy that does".
...Crusty Old Fart engine builder in my past
10-08-2009, 07:59 AM
#13
Are you going to spray or do some sort of FI? What are you looking to do?
The 427 is better if you are going to boost or going to spray more than a 200 shot if you are going to stay in the LS7 block.
The 440 LS7 4.13[5] x 4.100" in the LS7 is great for N/A motor, i would not spray more than a 200 shot because the cylinder walls are thinner and the piston pin is moved up some which makes for a thinner piston deck.
10-08-2009, 01:10 PM
#14
Do they measure 'em differently? 5.8" is 5.8", either way. Not trying to argue, just don't understand. I have a LS7 block and don't see any reason not to go with the longer stroke...it's only .100 longer than factory which puts the pin .050 higher in the piston. Unless you absolutely can't spare the .050, there's no reason to go that way.
"Build it as big and bad as you can, or you'll get tired of getting your a$$ handed to you by the guy that does".
...Crusty Old Fart engine builder in my past
"Build it as big and bad as you can, or you'll get tired of getting your a$$ handed to you by the guy that does".
...Crusty Old Fart engine builder in my past
Could have swore there was something undesirable with the factory LS7 sleeves.
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10-08-2009, 04:44 PM
#16
Its been awhile, but I remember someone telling me about a problem with a 4.125 stroke in the factory LS7 sleeves.
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10-09-2009, 02:43 PM
#17
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Biggest question!
Are you going to spray or do some sort of FI? What are you looking to do?
The 427 is better if you are going to boost or going to spray more than a 200 shot if you are going to stay in the LS7 block.
The 440 LS7 4.13[5] x 4.100" in the LS7 is great for N/A motor, i would not spray more than a 200 shot because the cylinder walls are thinner and the piston pin is moved up some which makes for a thinner piston deck.
Are you going to spray or do some sort of FI? What are you looking to do?
The 427 is better if you are going to boost or going to spray more than a 200 shot if you are going to stay in the LS7 block.
The 440 LS7 4.13[5] x 4.100" in the LS7 is great for N/A motor, i would not spray more than a 200 shot because the cylinder walls are thinner and the piston pin is moved up some which makes for a thinner piston deck.
. I am going back to NA and my goal is to build a bad high CR engine with out any power adders. Latter down the road i might add a little nitrous to the mix but i would prefer to make as much power as i can NA vs building it for nitrous.
10-09-2009, 05:23 PM
#18
That would be the question of the day . I am going back to NA and my goal is to build a bad high CR engine with out any power adders. Latter down the road i might add a little nitrous to the mix but i would prefer to make as much power as i can NA vs building it for nitrous.
. I am going back to NA and my goal is to build a bad high CR engine with out any power adders. Latter down the road i might add a little nitrous to the mix but i would prefer to make as much power as i can NA vs building it for nitrous.The 4.1 x 4.130 sounds like a good combo.
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10-09-2009, 09:45 PM
#20
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Is it possible to partially fill these blocks to strengthen the sleeves like is common with Gen 1 small blocks and big blocks? The sleeves in my LS7 block are basically siamesed, so they do get support on that axis, but is there any way to reinforce completely around the bottom 2/3 of the sleeves without significantly compromising cooling?
I wonder if a fella could get a few gallons of each part of JB Chemweld and grout a block with it? It does have aluminum in it and I swear if somebody put their mind to it, they could build a working small engine out of that stuff
I wonder if a fella could get a few gallons of each part of JB Chemweld and grout a block with it? It does have aluminum in it and I swear if somebody put their mind to it, they could build a working small engine out of that stuff