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11-06-2004, 03:22 AM | #1 |
DAMN, I love Big Blocks!
Join Date: Aug 2003
Location: New Mexico, USA
Posts: 619
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BBC "781" Cylinder Head Chamber Volume.
Does anyone have an absolute positive spec for the factory combustion chamber volume on unmodified "781" casting heads off of a 454 BBC? Some books say 109cc, some say 110cc, while others say 119cc. I know the only "true" way is with a burette and a cylinder head cc'ing kit, but I'm just looking to know if anyone has noticed all these varying figures and has an absolute answer. Again, my heads have never been planed or had the chamber modified......in fact, they've never even been off the engine! Anywho, thanks in advance, folks.
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Marc Bona Hobbs, New Mexico 1976 1/2 ton GMC High Sierra. 454 c.i.d./ TH400. *Soon to get a mild warming over.* 3.40 rear. |
11-06-2004, 06:03 PM | #2 |
paper or plastic?
Join Date: Nov 2002
Location: SW Missouri
Posts: 671
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I've got the same heads and was told they are 118cc but I have never checked.
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1967 Chevy SWB 250 http://67-72chevytrucks.com/vboard/s...d.php?t=442157 1977 Chevy SWB 454 No More 454 getting 5.3 http://67-72chevytrucks.com/vboard/s...d.php?t=310518 1977 Stepside Truck of the month winner http://67-72chevytrucks.com/vboard/s...d.php?t=135524 1965 Chevy C10 454 http://67-72chevytrucks.com/vboard/s...d.php?t=731372 1975 Dodge Power Wagon http://67-72chevytrucks.com/vboard/s...=1#post7871388 |
11-06-2004, 06:45 PM | #3 |
Registered User
Join Date: Oct 2002
Location: Murfreesboro Tennessee
Posts: 58
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They are 116 to 118 cc. If they've had big valves installed the right way, they'll often be between 112 and 114 cc. If they've been milled, they will be lower. You cannot flat mill those heads more than about 0.030" without hitting the intake valve seat, by the way.
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11-07-2004, 11:57 PM | #4 |
Registered User
Join Date: Sep 2004
Location: Elkins, West Virginia
Posts: 2,542
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i've got two sets in my garage...and a set of "049"s ....these two flow awesome man..... :p
perfect street head....there both 119cc's with stock valves i remember reading somewhere that the 781's flow around 260 stock -bigarmzz- |
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