GM Engine & Exhaust Performance EFI | GEN I/GEN II/GEN III/GEN IV Engines |Small Block | Big Block |

i want to build up a 4.8

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Old Jan 14, 2008 | 09:47 AM
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Default i want to build up a 4.8

i need help on finding what kind of pistons, rods, and crank
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Old Jan 14, 2008 | 11:33 AM
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Dang, Biggin, that's kind of a paucity of information there, don't you think? Are you planning to build a screamer or a torquer? FI or NA? Gonna over-bore it? How 'bout some more info on what you want.
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Old Jan 14, 2008 | 11:38 AM
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Not bashin you or anything, but why the interest in building up a 4.8? Class rules, spec class, love the short stroke, just cause?

If its the short stroke/fast rev aspect that pulls your trigger, why not find a way to put the 4.8 crank (3.26") into a 6.0 block (with its 4" bore) to make a true LS 327-ish engine. I'd love to see someone put that engine together, as I myself am a fan of the fast revving engines as well.
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Old Jan 15, 2008 | 09:12 AM
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well i want to keep at the stock bore...I want to build one up to around a 300 shot of nos...I have seen a 5.3 hold a 300shot stock but i dont want to risk blowing anything up...
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Old Jan 15, 2008 | 09:14 AM
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oh yeah sorry about the poor info when i get on the site im always in a hurry lol i thought i had more then that up there
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Old Jan 15, 2008 | 12:39 PM
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I don't understand why you would want to spend more money to have a smaller motor. No one makes a off the shelf forged piston or rods for the 4.8, so you would have to custom piston. You could use some aftermarket rods, but again, there are no direct replacements, so you would have to make your custom piston made to fit the rod also.

If you want to built a stout motor, your cheapest solution is to build an iron block 5.7. All you need is a crank from a 5.3,5.7 or 6l then some off the shelf forged pistons and rods and bore your 4.8 block to fit the piston. A bigger motor for less money, but that just my opinion.

Personally, I think these trucks are too heavy for a short stroke motor like the 4.8, and need the extra torque that you get with the longer stroke that the 5.7 would have. This is coming from a guy with a 500rwhp 4.8
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Old Jan 15, 2008 | 08:43 PM
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you know 4.8 and 5.3 are the same block right? might as well go with 5.3 internals
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Old Jan 15, 2008 | 09:05 PM
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I would bore it and make a 5.7 with ls1 pistons
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Old Jan 15, 2008 | 09:08 PM
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+1 on the 5.7
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Old Jan 16, 2008 | 02:29 AM
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see how much spray the stock engine will hold. It doesnt cost much to replace.

I like the iron 5.7 idea. how cheaply can it be done?
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