4.8 vs 5.3 Questions
08-31-2010, 08:35 PM
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4.8 vs 5.3 Questions I just want to verify something. I have a friend selling the 4.8 out of his truck. I did the research and found that the 4.8 and the 5.3 have the exact same bore but have different stroke. Now, my question is: Can I build the 347 that I want to build with a 4.8L block?
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08-31-2010, 09:05 PM
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haha....that's what I was making sure of. I know everyone builds the 347 which is 3.905 bore from a 5.3, so it should be possible with the 4.8 and my stock crank, correct?
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08-31-2010, 09:37 PM
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4.8 and 5.3 blocks are the same. The only way they really differentiate them from what I heard is a paint mark on the outside on the 4.8/5.3 numbers designating which it is. So yes you can build it, and actually make up to a 383 if you decided to go with a 4" stroker crank on the 3.905 bore.
The 4.8 shared the same bore as the 5.3, just had different pistons (flat top), as well as different rods and a different crank. The 5.3 has the same size rods and crank as the LS-1
The 4.8 shared the same bore as the 5.3, just had different pistons (flat top), as well as different rods and a different crank. The 5.3 has the same size rods and crank as the LS-1
09-01-2010, 08:24 PM
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I am internal engine retarded! If the bore size will be 3.905, then will I need to order 3.905 bore pistons? Do they come "sized" for the right bore? I'm sure that if the ID of the cylinder is 3.905 and the OD of the piston is 3.905, they ain't gonna fit! Another stupid question: What length rods for stock LS crank to make 347 c.i.d??
Any info any of you guys can give me is very much appreciated!
Any info any of you guys can give me is very much appreciated!
09-01-2010, 10:59 PM
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You are better off buying the pistons first before you have it bored, and take them with you to the machine shop so they can spec everything properly. Also 3.905 is an overbore of the stock ls1 bore (I believe its 3.898 without looking it up). You can also run standard bore ls1 pistons, just most aftermarket are 3.905.
I believe LS1 and 5.3 rods are 6.100", but there is also a slightly longer aftermarket rod offered at 6.125" to keep the rod more centered in the stroke.
Honestly for the sounds of it with the possible cost of boring, it may be cheaper to find another ls1 or ls6 block. There are plenty out there, especially with everyone switching to gen IV.
You can also take the 4.8 block, leave the 4.8 pistons and swap in a ls1 or 5.3 crank & rods. This will give you a high compression 5.3, which some others have done here, and actually had some impressive results.
It all depends on your intentions and goals, just have to figure them out, and as long as its cost effective that 4.8 can be built to 5.3 (323) 5.7 (346) or 6.3 (383)
I believe LS1 and 5.3 rods are 6.100", but there is also a slightly longer aftermarket rod offered at 6.125" to keep the rod more centered in the stroke.
Honestly for the sounds of it with the possible cost of boring, it may be cheaper to find another ls1 or ls6 block. There are plenty out there, especially with everyone switching to gen IV.
You can also take the 4.8 block, leave the 4.8 pistons and swap in a ls1 or 5.3 crank & rods. This will give you a high compression 5.3, which some others have done here, and actually had some impressive results.
It all depends on your intentions and goals, just have to figure them out, and as long as its cost effective that 4.8 can be built to 5.3 (323) 5.7 (346) or 6.3 (383)
09-02-2010, 01:15 PM
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Does anyone know what the Max lift on those truck head valve springs? I have a 2008 4.8 and doin a cam swap without changing my springs. What the Max I can go. Sorry to bump into someone else's thread
09-02-2010, 01:26 PM
#12
.525 more realistic. esp if have lot of miles on stock springs.
dont make sense to use aftermarket cams with stock springs. unless your using a gm hot or ls6 cam. even then you should at least upgrade to ls6/ls2 springs.
09-02-2010, 01:53 PM
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Yeah I was goin to ls6 cam. So stock springs for a ls6 would go right on my truck heads? 01 ls6 goes .525 on lift but 02+ goes. 556 I think. So if I used ls6 springs with my ls6 cam I should b good? Where can I go to get stock replacement parts like that?
09-02-2010, 05:20 PM
#14
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I just want to verify something. I have a friend selling the 4.8 out of his truck. I did the research and found that the 4.8 and the 5.3 have the exact same bore but have different stroke. Now, my question is: Can I build the 347 that I want to build with a 4.8L block?
I think you are trying to do things the hard way. You would be better off buying a used 6.0 iron block truck engine. The heads are better than the 4.8's, and you can have more power for less work ($).
My $.02
Jon
09-02-2010, 08:01 PM
#19
to bore or not this is just my 2 cents. why would anyone go thru the trouble of a rebuild bore/stroke any lsx motor? if u truly know them, then u must know they are all great from the start. i have a buddy with a carbed 4.8, & it is scary. trust me when i say he believes in laughing gas. most all to the truck motors can be had for reasonable price, from the bone yards. once you go thru the trouble of buying new pistons, crankshaft, rings, balance internals, machining the block and trust that the machine shop is on point with measurements, that cost will more than offset a new lsx motor. i will never rebuild another motor unless lsx motors are discontinued in the junk yards, and by that time ill have a hotrod spaceship.
09-02-2010, 08:25 PM
#20
this is just my 2 cents. why would anyone go thru the trouble of a rebuild bore/stroke any lsx motor? if u truly know them, then u must know they are all great from the start. i have a buddy with a carbed 4.8, & it is scary. trust me when i say he believes in laughing gas. most all to the truck motors can be had for reasonable price, from the bone yards. once you go thru the trouble of buying new pistons, crankshaft, rings, balance internals, machining the block and trust that the machine shop is on point with measurements, that cost will more than offset a new lsx motor. i will never rebuild another motor unless lsx motors are discontinued in the junk yards, and by that time ill have a hotrod spaceship.
If ur looking for more cubes just buy a stock 6liter they can be had for about 800$ but if u must have the 4.8 leave it stock and put boost to it
