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Joined: Nov 2013
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These seem to be pretty good with closed chambers and 72 cc. will give my 400 9.2 CR up from 8 right now. What are you thoughts on these 670 heads? http://www.kijiji.ca/v-engines-and-engin...s-670/598340877
Last edited by Kyle; 09/04/14 10:01 AM.
1968 Firebird, 350 4V, TH350 with trans-go, 69 slap shifter, 8.5 inch 10 bolt 3.42 posi 
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Joined: Mar 2012
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Don't assume on CC of heads, they all should be checked. You should figure in the cost of machine work for a rebuild. I personally don't recommend re using 40+ year old valves on any rebuild.
Pontiac power
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Joined: Jul 2003
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67 400's with 670 heads had 10.75:1 CR. It should be the same with a 78 400.
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Joined: Dec 2005
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If untouched could be any where from 72-74cc.
And cr may not be 9.2 if go'n by specs with 78 factory stock pistons since they are chamfered on the outside.
Last edited by Region Warrior; 09/04/14 08:46 PM.
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Joined: Nov 2013
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The pistons are crappy cast stock replacement 30 over from an older rebuild they aren't chamfered, but have the 8 valve reliefs. I cc'd them, they are 14ccs. .025 in the hole.
Current heads are ported 6x-8 milled to 90cc, I cc'd them.
What is the ball park figure on a rebuild?
Thanks!
Last edited by Kyle; 09/06/14 10:18 PM.
1968 Firebird, 350 4V, TH350 with trans-go, 69 slap shifter, 8.5 inch 10 bolt 3.42 posi
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