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Old 09-29-2010, 10:59 PM   #1
dwcsr
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4.8 to 5.3 conversion cam question

I have a 4.8 I'm making a 5.3. I have the floating pin flat top pistons, 862 heads and a cam with .467/.479 lift from an LS1. The stock lift is .457/.466.

The questions I have are do I need to use other than the stock 862 valve springs and do I need to be worried about the piston hitting the valve with the flat tops.

My thinking was its almost stock and should be no issue but I'm not up on LSx motors
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Old 09-29-2010, 11:38 PM   #2
68GMCCustom
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Re: 4.8 to 5.3 conversion cam question

...now I thought the bore of the 4.8L and 5.3L was the same...and that the stroke was different.....
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Old 09-30-2010, 12:09 AM   #3
dwcsr
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Re: 4.8 to 5.3 conversion cam question

Quote:
Originally Posted by 68GMCCustom View Post
...now I thought the bore of the 4.8L and 5.3L was the same...and that the stroke was different.....
correct, I should have said I changed the crank, rods and piston to make it a 5.3

Last edited by dwcsr; 09-30-2010 at 12:09 AM.
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Old 09-30-2010, 01:14 AM   #4
Super73
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Re: 4.8 to 5.3 conversion cam question

If you have 5.3 rods and pistons you should be fine. If you have 4.8 rods with 5.3 pistons, I can't answer your question as I don't know the rod length...
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------Motor---------------Bottle
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1/8---6.58 @ 105.92----5.87 @ 118.41
1/4---10.38 @ 126.97----9.24 @ 142.49
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Old 09-30-2010, 02:22 AM   #5
dwcsr
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Re: 4.8 to 5.3 conversion cam question

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Originally Posted by Super73 View Post
If you have 5.3 rods and pistons you should be fine. If you have 4.8 rods with 5.3 pistons, I can't answer your question as I don't know the rod length...
I purchased a 5.3 crank, rods and flatop pistons. I thought it would be ok but didn't know for sure.
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Old 10-07-2010, 09:14 PM   #6
blazerboy72
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Re: 4.8 to 5.3 conversion cam question

Do you have 4.8 rods and pistons too? The 5.3HO is really just a 4.8 with a 5.3/6.0 crank, if you want a little extra compression.
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