benefit of milling heads??
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Re: benefit of milling heads?? I thought I read somewhere that the SPDC ported LS-6 heads (about $900 each complete with springs and valves and the porting is done by lingfelter) were milled .055 and that the estimated static compression was around 11 to 1. ...so if .033 is about 2/3 of .o55 it would increase compression by 2/3 of the difference between stock 10.25 to 1 and 11.0 to 1.
you need to cut down the alignment pins on the plastic manifold if u use milled, heads, however....
you need to cut down the alignment pins on the plastic manifold if u use milled, heads, however....
TECH Fanatic
Joined: Nov 2001
Posts: 1,975
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From: SW Florida
Re: benefit of milling heads?? I am having my ported 5.7 heads milled .035"
In addition, a TR-220 cam will be installed.
Below is what I understand to be true:
Milling 5.7 LS1 heads .035” will decrease the stock 67.3cc chamber volume to approx 63cc
This will yield a 10.7 to 1 compression ratio when the stock GM .052" thick graphite head gaskets are used.
In addition, a TR-220 cam will be installed.
Below is what I understand to be true:
Milling 5.7 LS1 heads .035” will decrease the stock 67.3cc chamber volume to approx 63cc
This will yield a 10.7 to 1 compression ratio when the stock GM .052" thick graphite head gaskets are used.
Re: benefit of milling heads?? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2002snortbird:
<strong>OK, what are the pros and cons of a higher cr??</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">pro - rwhp <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
con - knock retard ( need higher octane fuel )
<strong>OK, what are the pros and cons of a higher cr??</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">pro - rwhp <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
con - knock retard ( need higher octane fuel )
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: benefit of milling heads?? Milling heads will help restore some of lost cylinder pressure from cam size increase. Higher compression will extend powerband some by keeping some extra cylinder pressure as VE falls off from heads flow and or cam limits. Detonation can be relieved with rear gear changes, weight reduction, custom timing and A/F ratio tweaks with PCM. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
