what i need to take into consideration before buying heads?
09-11-2003, 06:00 PM
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what i need to take into consideration before buying heads? what do these different heads do or change about my motor 5.3,5.7,6.0? compression? etc..
what type of springs etc....
thanks
what type of springs etc....
thanks
09-11-2003, 10:58 PM
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Re: what i need to take into consideration before buying heads? In a nutshell, here goes:
A 5.3 head has a smaller combustion chamber than a 5.7 and will effectively bump the compression for a small gain in power.
The 5.7 heads are the same ones on the engine right now. The compression ratio will remain the same, save for any milling you specify to raise it.
A 6.0 head has a larger CC and will effectively lower the compression ratio. This makes it a popular head choice for forced induction applications because generally F/I and high compression do not like one another.
As for springs, it really depends on the cam you choose. If you stay around .580 lift, you can use a single spring (i.e. Comp "918"). If you anticipate going with a higher lift, consider a dual spring for reliability issues. Going .600 lift is the max I'd trust 918's for any length of time.
A 5.3 head has a smaller combustion chamber than a 5.7 and will effectively bump the compression for a small gain in power.
The 5.7 heads are the same ones on the engine right now. The compression ratio will remain the same, save for any milling you specify to raise it.
A 6.0 head has a larger CC and will effectively lower the compression ratio. This makes it a popular head choice for forced induction applications because generally F/I and high compression do not like one another.
As for springs, it really depends on the cam you choose. If you stay around .580 lift, you can use a single spring (i.e. Comp "918"). If you anticipate going with a higher lift, consider a dual spring for reliability issues. Going .600 lift is the max I'd trust 918's for any length of time.
09-12-2003, 12:12 AM
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Re: what i need to take into consideration before buying heads? What he said,
also if you plan on getting ported heads most stage II's will already be machined for the larger dual springs. This like many are finding means either modifing or replacing the stock rockers(clearance issues). Stage I's depending on the manufacturer may not be machined for the larger dual springs, meaning smaller cams for safety and limitation of spring reasons.
also if you plan on getting ported heads most stage II's will already be machined for the larger dual springs. This like many are finding means either modifing or replacing the stock rockers(clearance issues). Stage I's depending on the manufacturer may not be machined for the larger dual springs, meaning smaller cams for safety and limitation of spring reasons.
09-12-2003, 12:49 AM
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Re: what i need to take into consideration before buying heads? I'd consider the fact that AFR is supposed to come out w/ some NICE sets in about 6 months or so. 
09-12-2003, 12:54 AM
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Re: what i need to take into consideration before buying heads? If you are also thinking about running a big cam you also have to watch what heads you choose, due to the piston to valve clearance, if your heads are milled....
I had an issue with .30milled 5.7L heads with a .591 lift cam...
I had an issue with .30milled 5.7L heads with a .591 lift cam...
09-12-2003, 11:29 AM
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Re: what i need to take into consideration before buying heads? Im looking for stage II heads
currently i have a 222/224 114 .574 cam
but i want to go bigger, something around 227-229
i defintly dont want 6.0 heads because im staying N/A.
I will be doing the water pump,oil pump and timing chain at the sametime also.
is there anything else i should do while its opened?
Is there advantages going with a dual spring?
thanks guys
currently i have a 222/224 114 .574 cam
but i want to go bigger, something around 227-229
i defintly dont want 6.0 heads because im staying N/A.
I will be doing the water pump,oil pump and timing chain at the sametime also.
is there anything else i should do while its opened?
Is there advantages going with a dual spring?
thanks guys
