Why do people use 5.3 heads instead of 5.7's
09-10-2002, 06:42 PM
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Why do people use 5.3 heads instead of 5.7's I was just wondering why does it seem that the 5.3 heads produce more power. Does it raise the compression higher then 5.7's? Or can you fit bigger vavles in the 5.3's?
09-10-2002, 06:57 PM
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Re: Why do people use 5.3 heads instead of 5.7's </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Savageite:
<strong>I was just wondering why does it seem that the 5.3 heads produce more power. Does it raise the compression higher then 5.7's? Or can you fit bigger vavles in the 5.3's?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Main reason is cost. There are so many more 5.3L heads out there that they are cheap cores.
Other reasons:
Since most people change the valve sizes when they are ported there is no need to use 5.7 and up heads.
The other thing is that the 5.3L heads have more material to port. That might sound like it's more work but it also means that the meat is in some areas where you want it. This in turn alows you to have high flow, high velocity and smaller port volume. That means more area under the TQ curve.
That can be disputed, that you either want high rpm power for racing and the such, but that's others opinions, mine is not that. I like torque plain and simple.
Bret
<strong>I was just wondering why does it seem that the 5.3 heads produce more power. Does it raise the compression higher then 5.7's? Or can you fit bigger vavles in the 5.3's?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Main reason is cost. There are so many more 5.3L heads out there that they are cheap cores.
Other reasons:
Since most people change the valve sizes when they are ported there is no need to use 5.7 and up heads.
The other thing is that the 5.3L heads have more material to port. That might sound like it's more work but it also means that the meat is in some areas where you want it. This in turn alows you to have high flow, high velocity and smaller port volume. That means more area under the TQ curve.
That can be disputed, that you either want high rpm power for racing and the such, but that's others opinions, mine is not that. I like torque plain and simple.
Bret
09-10-2002, 07:19 PM
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Re: Why do people use 5.3 heads instead of 5.7's Cool thanks for the information. I never really thought about how many more 5.3's there are then 5.7's.
09-10-2002, 07:35 PM
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Re: Why do people use 5.3 heads instead of 5.7's Well what was the deal on using the 4.8 head like they did in the GMHTP article ! <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
09-10-2002, 07:42 PM
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Re: Why do people use 5.3 heads instead of 5.7's </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Orange Krush:
<strong>Well what was the deal on using the 4.8 head like they did in the GMHTP article ! <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The 4.8 and 5.3 truck heads are identical.
Another benefit of the 4.8/5.3 head is the smaller combustion chamber. This will bump the compression up with very minimal milling. This is a great option when trying to fit a large cam where piston to valve clearance might be an issue.
Jason
<strong>Well what was the deal on using the 4.8 head like they did in the GMHTP article ! <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The 4.8 and 5.3 truck heads are identical.
Another benefit of the 4.8/5.3 head is the smaller combustion chamber. This will bump the compression up with very minimal milling. This is a great option when trying to fit a large cam where piston to valve clearance might be an issue.
Jason
