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Old 09-18-2004 | 07:29 AM
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Default piston swap

Hey,

4.8L pistons are flat tops, 5.3's aren't correct? Same bore.

What all is needed to swap 4.8 pistons into a 5.3? Is it possible?
One more question to refresh my memory. What is wrong with excesive milling to the cylinder heads? What problems do you run into again. Or what needs to be changed with say a .040 off the deck?

p.s. please, no why dont you get a 6.0L responses. please

Thanks guys,

Kyle
Old 09-18-2004 | 09:24 AM
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Dont knowa bout the pistons but excessive milling to the heads could mean needing to make sure the valves wont hit the piston, possibly if enough is taken push rods might be an issue ,maybe.
Old 09-18-2004 | 10:03 AM
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You are correct abou tthe pistons. I don't know how much of a difference in compression it would make, but I'm thinking unless you just happened to have 2 motors laying around it wouldn't be worth it.

WIth excessive milling you run into piston/valve clearance issues and problems with valvetrain geometry.
Old 09-18-2004 | 10:46 AM
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Why don't you get a 6.0? JFWY
Old 09-18-2004 | 11:02 AM
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Yes, I didn't state that in my initial post. Looking for higher compression. Thats why I'm interested in the 4.8 piston.

I believe I'd have to find a custom piston to fit the 5.3 bore and that can get pricey. Might have to just bore the block and find a domed piston.

Any opinions, please post. If you have any information about the 4.8 piston, I'm still listening so post up.

15sec5.3 ---->
Old 09-18-2004 | 11:31 AM
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The 4.8's are flat I think.

Here is a 5.3 piston:


If you were to buy custom pistons, it would be about 500 bucks, and roughly 125 for rings. At this point it would be wiser to buy a 6.0 and stick in there.
Old 09-19-2004 | 08:45 AM
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Thanks, for the picture Flyer. Would you happen to be able to pin point me where I can find custom pistons for $500?

Thanks again.
Old 09-19-2004 | 09:53 AM
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Diamond Pistons ----->
Old 09-20-2004 | 10:58 AM
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Default 4.8 Piston

Originally Posted by SportSide 5.3
Hey,

4.8L pistons are flat tops, 5.3's aren't correct? Same bore.

What all is needed to swap 4.8 pistons into a 5.3? Is it possible?
One more question to refresh my memory. What is wrong with excesive milling to the cylinder heads? What problems do you run into again. Or what needs to be changed with say a .040 off the deck?

p.s. please, no why dont you get a 6.0L responses. please

Thanks guys,

Kyle
Kyle,

The 5.3 piston dish volume is 8.14 cc. By using a 4.8 flat top piston, you will effectively reduce your trapped volume by that amount. The 4.8 and 5.3 heads are the same with a combustion chamber volume of 61.15 cc. You do the math, and let us know what the CR wil be. Rough calc says over 11:1.

Andy
Old 09-20-2004 | 01:16 PM
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Andy,

Thanks for the info.

So then, the 4.8 piston will work? Do you know if I'll need anything else done to the bottom end to make it fit right?

Thanks


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