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906 Heads True Combustion chamber cc??

Posted By: 540challenger

906 Heads True Combustion chamber cc?? - 11/16/09 02:37 PM

Has anyone CCed the combustaion chamber on Big block 906 heads. I have a buddy geting a motor built and the guy puting the motor together for him said that they CCed at 78 CC and they were never milled This doesn't seem right to me. Thanks for the help/
Posted By: lewtot184

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 02:44 PM

an unmilled head will vary between 88cc-90cc, usually closer to 88cc.
Posted By: momopar

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 02:49 PM

Isn't the "blueprint" for a 906 79.5cc?
Posted By: 540challenger

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 02:52 PM

Quote:

Isn't the "blueprint" for a 906 79.5cc?

I think the guy putting this together went by blue-print spec instead of actually CCing the heads. The blue pritned numbers are all fudged numbers.
Posted By: 540challenger

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 02:53 PM

Quote:

an unmilled head will vary between 88cc-90cc, usually closer to 88cc.

thank you
Posted By: JohnRR

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 03:51 PM

Quote:

Isn't the "blueprint" for a 906 79.5cc?



NO ,That is the NHRA spec which doesn't remotely resemble actual , which is usually 90 cc , I have a bunch and never seen any under 90cc that haven't been decked.

If the shop cc'd them and they are 78 they have been decked , A LOT .
Posted By: Dodgem

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 03:51 PM

The numbers are not fudged they were designed to be 78.5 (by the blue prints) but any I ever checked were 86 to 88. I milled a set to 63 cc (about .105 to .110 off) turned them into closed chamber!! They worked good for a few years till one cracked back in the intake port where the porting had made it thin!
Posted By: NachoRT74

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 03:52 PM

I got 92s on my 452s. Specs on websites states 84... GO FIGURE
Posted By: Dodgem

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 03:55 PM

Yea the 452's were mostly 90/92 as cast!
Posted By: moper

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 04:41 PM

90-92 as cast.
Posted By: 67 GTX

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 05:50 PM

My 906 heads milled 0.010 measured to be 84 cc.
Posted By: ademon

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 06:47 PM

i have a couple sets of 915 close chamber heads the one i used on my RR cc at 80cc with the small exh, most opens were 90 + then add a couple valve jobs where the valve sinks add more cc's. If you have replaced the valves with ones that are not concaved like the factory ones then you could cut down the cc's buy a bit.
Posted By: PAINT IT BLACK

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 07:23 PM

I had mine cc'd and it came out to 93+cc
Posted By: joedust451

Re: 906 Heads True Combustion chamber cc?? - 11/16/09 08:14 PM

I CC'd a set & they were 91.
Posted By: gregsdart

Re: 906 Heads True Combustion chamber cc?? - 11/03/19 02:06 AM

Originally Posted by Dodgem
The numbers are not fudged they were designed to be 78.5 (by the blue prints) but any I ever checked were 86 to 88. I milled a set to 63 cc (about .105 to .110 off) turned them into closed chamber!! They worked good for a few years till one cracked back in the intake port where the porting had made it thin! <img src="/ubbthreads/images/graemlins/shruggy.gif" alt="" />

I had a set cut like that. Under a black light they looked like a lit christmas tree after a few seasons!
Posted By: Sniper

Re: 906 Heads True Combustion chamber cc?? - 11/03/19 02:08 AM

do you realize this ia a ten year old thread?
Posted By: Cab_Burge

Re: 906 Heads True Combustion chamber cc?? - 11/03/19 02:51 AM

Every stock 906 I've check had 90+ CC, every one of many, the chambers will vary from 2.0 to 4.5 CC on the same head also puke
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