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Milling and big block cylinder heads...
#341061
06/07/09 11:17 PM
06/07/09 11:17 PM
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Joined: Oct 2004
Posts: 16,477
Canada
CrAzYMoPaRGuY
OP
I Live Here
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OP
I Live Here
Joined: Oct 2004
Posts: 16,477
Canada
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OK, here's the scenario...
I have a pair of heads off an engine and I want to cut them .030".... BUT the surface of the heads look odd to me, and I am wondering if they have ALREADY been cut....
They are 1974 440 heads, 3769902 heads. Can I measure from the base of where the lower head bolts go - down to the deck surface, or ...? How can I tell if they have been milled or not?
Anybody got any methods??
CrAzYMoPaRGuY
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Re: Milling and big block cylinder heads...
[Re: CrAzYMoPaRGuY]
#341062
06/07/09 11:31 PM
06/07/09 11:31 PM
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Joined: Jun 2008
Posts: 565
IA
landon1
mopar
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mopar
Joined: Jun 2008
Posts: 565
IA
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i heard 1" height were lower head bolts go....but when you're talking thousandths of an inch, idk how accurate that can be - best bet is to CC them
'71 Satellite Sebring 440
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Re: Milling and big block cylinder heads...
[Re: landon1]
#341064
06/07/09 11:39 PM
06/07/09 11:39 PM
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Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
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Quote:
i heard 1" height were lower head bolts go....but when you're talking thousandths of an inch, idk how accurate that can be - best bet is to CC them
this is correct very close , plus minus .005ish to 1.000 ..
902 is an open chamber head ??? , 81.5 cc ?? 
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Re: Milling and big block cylinder heads...
[Re: JohnRR]
#341065
06/07/09 11:42 PM
06/07/09 11:42 PM
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Joined: Jun 2008
Posts: 565
IA
landon1
mopar
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mopar
Joined: Jun 2008
Posts: 565
IA
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i think that the 906, 346, 452 heads are all about 86-88 CCs aren't they? i had never heard 81.5
'71 Satellite Sebring 440
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Re: Milling and big block cylinder heads...
[Re: landon1]
#341066
06/07/09 11:43 PM
06/07/09 11:43 PM
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Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
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Quote:
i think that the 906, 346, 452 heads are all about 86-88 CCs aren't they? i had never heard 81.5
90-92
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Re: Milling and big block cylinder heads...
[Re: CrAzYMoPaRGuY]
#341067
06/07/09 11:44 PM
06/07/09 11:44 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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the factory milled head decks with a straight cutter & MOST machine shops use a circular milling machine so if the marks are circular you know for sure that it's been cut on.
live every 24 hour block of time like it's your last day on earth
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Re: Milling and big block cylinder heads...
[Re: RapidRobert]
#341068
06/07/09 11:45 PM
06/07/09 11:45 PM
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Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
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Quote:
the factory milled head decks with a straight cutter & MOST machine shops use a circular milling machine so if the marks are circular you know for sure that it's been cut on.
A straight cutter ???
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Re: Milling and big block cylinder heads...
[Re: CrAzYMoPaRGuY]
#341072
06/07/09 11:59 PM
06/07/09 11:59 PM
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Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
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Quote:
Quote:
i think that the 906, 346, 452 heads are all about 86-88 CCs aren't they? i had never heard 81.5
I went and checked a half dozen sites, all were 81.5 cc for the 902 heads....
3769902 1974 440 400 2.08" 1.74" 81.5cc
http://www.motortopia.com/forums/viewtop.../tp/1#post_3902
they list the 906 at 79.5cc , thats the NHRA blueprint spec . measure what you ACTUALLY have , do not believe everything you read ...
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Re: Milling and big block cylinder heads...
[Re: RapidRobert]
#341073
06/08/09 12:00 AM
06/08/09 12:00 AM
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Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
1_WILD_RT
Management Trainee
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Management Trainee
Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
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FWIW whether they have been milled or not is less important than the final chamber volume, measure them now & cut them to obtain the volume you need to get the C/R you want...  BTW .0062 off the deck = 1cc & for every .010 off the deck cut the intake surface of the head .0123 And BTW John is absolutely right.. Blueprint spec isn't even close to what Mopar really supplied.. 88cc happened allot less than 91-92cc
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Re: Milling and big block cylinder heads...
[Re: CrAzYMoPaRGuY]
#341080
06/08/09 12:08 AM
06/08/09 12:08 AM
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Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
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Quote:
Quote:
FWIW whether they have been milled or not is less important than the final chamber volume, measure them now & cut them to obtain the volume you need to get the C/R you want...
BTW .0062 off the deck = 1cc & for every .010 off the deck cut the intake surface of the head .0123
Therein lies a small problem and why I posted this....
Who knows if the heads have been shaved... they look like they have, but the intake surfaces look stock. If they were cut already the .0123 certainly hasn't been taken off. I just wonder if there is a way to determine what the factory height off some point on the head to the deck surface or something, so I have SOME kind of bearing...
It is not surprising to see the intake side not cut , that cost EXTRA over the deck mill .
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