INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Building a 4.8

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Old Jul 15, 2010 | 12:30 PM
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Default Building a 4.8

I know it's only a 4.8l but I couldnt pass up the deal. Picked up a used 4.8 out of a wrecked truck for only $300 with everything but the alternator a/c brakets.

Anyways, i'm trying to see what direction to go with it, and I jut had a few questions.

What is Max bore on this block? I know the stock bore is: 3.779'' (96mm)

Stroke is 3.267'' (83mm)

Is it possible to bore it out to a 327 ci? I know a small block is 3.25 bore and 4'' stroke so it's pretty close.

If there are any other comments or suggestions anyone has it would be great.
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Old Jul 15, 2010 | 12:33 PM
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If you would've searched you would've already known that the answer is going to be "Build an Iron LS1".
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Old Jul 15, 2010 | 06:23 PM
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agreed. you can bore it out to an ls1 bore. bout 3.89 - 3.90 and can stroke it to a 383 with 4" crank then. and the block will say 4.8l. lol
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Old Jul 15, 2010 | 08:32 PM
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Yeah but whats the point, i'm making 600HP/TQ+ on a small turbo, thats with me tuning very safe because it's all stock. Get a set of good springs, good internals, rev it to 7-7.5k and put a big turbo on it. 750HP+, or whatever you really want and 3k of usable powerband.

To each their own, but I think a high revving 4.8L would be a fun setup.

However, if your stayin N/A, thats a different story.
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Old Jul 15, 2010 | 09:06 PM
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thanx foose, you brought a very good point. think thats the reason the op started this thread. to get an idea of which way to take this project. so now he has options for na and fi.
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Old Jul 15, 2010 | 09:13 PM
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I say yes to the ls1 bore 4.8 rods and stroke!! I am not 100% sure, but the newer 4.8 may have a HD rod like the 06+ 5.3's do. that would make a 8000 rpm monster!!
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Old Jul 15, 2010 | 09:15 PM
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Originally Posted by foose04
Yeah but whats the point, i'm making 600HP/TQ+ on a small turbo, thats with me tuning very safe because it's all stock. Get a set of good springs, good internals, rev it to 7-7.5k and put a big turbo on it. 750HP+, or whatever you really want and 3k of usable powerband.

To each their own, but I think a high revving 4.8L would be a fun setup.

However, if your stayin N/A, thats a different story.
that is one nasty 4.8 you got there. makes me think mine will take whatever abuse i give it. haha.

on a side note has anyone done a built 4.8? at least forged rods and pistons? crank failures seem to be very rare but callies does make some shorter stroke ones that come up on ebay once in a while
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Old Jul 15, 2010 | 09:20 PM
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no reason to uprade the internals anytime soon. i was around 800rwhp for quite awhile in my 4.8 on the street and had no issues at 7500 rpms every single shift

however a thought of mine is 4.8 stroke with LS1 bore for a 310 cube motor that can spool a larger turbo easiler and have same rpm capabilites
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Old Jul 15, 2010 | 09:46 PM
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Keep the 4.8 block and pistons, buy a cheap 5.3 crank and rods then you will have a stout little flat-top 5.3. Will be around 10.3:1 CR vs standard 5.3 9.5:1 CR.
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Old Jul 15, 2010 | 09:54 PM
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Originally Posted by kazfan30
Keep the 4.8 block and pistons, buy a cheap 5.3 crank and rods then you will have a stout little flat-top 5.3. Will be around 10.3:1 CR vs standard 5.3 9.5:1 CR.
Hush up man, that was my idea, I just was thinking the piston height was gonna screw me. Now that I know it wont..........................


(I know it wasnt my idea, just playing)
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