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

4.8 engine build question

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Old Apr 17, 2012 | 12:22 AM
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Default 4.8 engine build question

will my flat top pistons work if i put in 5.3 crank and rods? tryin to build a torquer motor for a daily driver 4x4.
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Old Apr 17, 2012 | 12:41 AM
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You can, and you'd have a 9.95:1 CR 5.3 liter(depending on heads). GM does it with an aluminum block and 799 heads, and calls it the L33 5.3HO.
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Old Apr 17, 2012 | 04:08 AM
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NNBS trucks also use flat top pistons
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Old Apr 17, 2012 | 08:34 AM
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Good deal, I was hoping they would. thanks for the replies.
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Old May 2, 2012 | 10:25 PM
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Hmmm, I thought the compression height on the 4.8 piston was different because the rod length is different between the 4.8 and 5.3.
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Old May 2, 2012 | 11:14 PM
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Originally Posted by BadSR71
Hmmm, I thought the compression height on the 4.8 piston was different because the rod length is different between the 4.8 and 5.3.
Nope.

Rod is different because the 4.8 crank has a shorter stroke.
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Old May 2, 2012 | 11:18 PM
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Didn't TurboGibbs calculate a different compression height for them?
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Old May 2, 2012 | 11:39 PM
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I've verified GM part numbers in the past, when I was researching this. The L33 piston part number is the same as the 4.8 liter piston.

Here's a pic of an L33 piston & rod above an older 4.8 piston & rod.
Name:  d720e505.jpg
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I'll have another LM7 apart soon, and I still have a set of 4.8 pistons here. I suppose I can take some measurements if that would make you a believer.
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Old May 3, 2012 | 12:40 AM
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No, that's good enough evidence for me lol. thanks
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