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2010 Dodge Challenger R/T
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Discussion Starter #1
5.7L Eagle heads combustion chamber is 65cc's, the current Edelbrock offering is 73cc (67cc & 83cc to come). What effect would the larger combustion chamber have on my performance? Will it lower the compression ratio and decrease performance? Or am I on the wrong planet? They are claiming 26 hp when added to a supercharged motor. I'm 432 rwhp on an moderate cam, ported intake, full exhaust, NA motor, how much of that 26hp would I see.
I know this is speculation. Opinions are appreciated. With the upgrade the heads flow, from 331 to 348.

Regards,
Mark
 

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I will give an opinion . yes 73 cc chamber will lower compression along with HP and TQ . even if you could get the 65 cc chambers these heads really don't offer much improvement over what you have already . flow improves from 331 to 348 . at what valve lift ? will your moderate lift cam even reach to the 348 cfm ? have you seen the low lift numbers ?( .200-.400 range ) any flow increase there is likely minimal at best... these heads appear to me to be the typical " ho hum " Edelbrock stuff . more like stock replacements than performance.
doesn't Arrington/ HHP/ Modern muscle have CNC ported 5.7 heads ? if not find a head porter who has CNC programs for the 5.7 and get your heads done. .
 

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5.7L Eagle heads combustion chamber is 65cc's, the current Edelbrock offering is 73cc (67cc & 83cc to come). What effect would the larger combustion chamber have on my performance? Will it lower the compression ratio and decrease performance? Or am I on the wrong planet? They are claiming 26 hp when added to a supercharged motor. I'm 432 rwhp on an moderate cam, ported intake, full exhaust, NA motor, how much of that 26hp would I see.
I know this is speculation. Opinions are appreciated. With the upgrade the heads flow, from 331 to 348.

Regards,
Mark
You dont mention ported heads in your list of mods. Those will always help with an aftermarket cam. Those edelbrock heads are an improvement but I would still port them before install. If you dont have that kind of experience, I would buy those same heads and send them out or take them to a shop that does cylinder head porting and polishing. That or just do the same to your stock heads. The edelbrock does have larger valves though so they are better in that respect. You should see 25-30rwhp gains from properly ported heads.

FYI: getting the 67cc edelbrock heads will not drop your compression anything major. Maybe see a loss of a couple hp. Nothing actually noticeable.
 

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OP has an NA cammed motor, not a blown motor. He was using edelbrocks numbers.
 

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Hello everyone.

Just wanted to jump in here and let you all know that we will be releasing a 67cc and 83cc version of our Edelbrock Gen III Hemi Cylinder Heads very soon.

These heads will be identical to the 73cc version (PN 61119) already released except for the combustion chamber size.

Let me know if you have any questions. :cheers:
 

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Discussion Starter #8
Any word on 67CC release?

Mark
 

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The 67cc heads are currently available to order. PN 61149 for the bare head, and 61159 for the complete head. Expected to ship mid to late February 2018.
 
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