changing compression w/LQ4 heads??
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changing compression w/LQ4 heads?? I know there are a few practical ways to change compression ratios on 346... either dished pistons or larger combustion chambers. It almost seems like the LQ4 heads are a great choice because they lower your compression ratio to about 9:1 while giving you improved flow through larger valves.
What I want to know is does the fact that the LQ4 heads are set up for a wider bore create any problems? Will the narrower bore shroud the valves? Does the narrower bore change the shape of the combustion chamber? Any other downsides of using LQ4 heads to lower compression?? I know we're talking about .1" which isn't THAT much, but still you never know...
My goals are to get the combustion chamber size down to somewhere between 8.5 and 9:1. Any thoughts? Any advantages to sticking with the original 346ci heads? Anyone ever use an LQ4 head AND dished pistons? What kind of boost are you 346 guys running at your given compression ratios?
I know it's a lot... just trying to decide how I want to drop my CR.
What I want to know is does the fact that the LQ4 heads are set up for a wider bore create any problems? Will the narrower bore shroud the valves? Does the narrower bore change the shape of the combustion chamber? Any other downsides of using LQ4 heads to lower compression?? I know we're talking about .1" which isn't THAT much, but still you never know...
My goals are to get the combustion chamber size down to somewhere between 8.5 and 9:1. Any thoughts? Any advantages to sticking with the original 346ci heads? Anyone ever use an LQ4 head AND dished pistons? What kind of boost are you 346 guys running at your given compression ratios?
I know it's a lot... just trying to decide how I want to drop my CR.
Us truck guys use the LQ4 heads on our 5.3s (325ci) without any problems. It's a nice set-up to lower our CP below the 9:1 mark. If I remember correctly some of the 293ci guys are using them too, I know I will be when I go FI.
Philip S.
Philip S.
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FI 346/LQ4 head guys - what CR and boost you running? Yea... I actually looked at the sticky on the LS1 Internal Engine section and it will bring it to about 9.2:1... anyone using the LQ4 heads in an FI setup? What kind of CR are you running at what boost?
Originally Posted by Pro Stock John
I think the compression drop is not to 9:1, but maybe 9.5:1. Going from a 72cc head from a 67cc head.
