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Re: Milling and big block cylinder heads... [Re: JohnRR] #341081
06/08/09 12:08 AM
06/08/09 12:08 AM
Joined: Aug 2007
Posts: 6,089
Valencia, España
NachoRT74 Offline
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NachoRT74  Offline
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Valencia, España
Quote:

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 ...




thats what made me choose some stuff "wrong"


With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Milling and big block cylinder heads... [Re: 1_WILD_RT] #341082
06/08/09 12:10 AM
06/08/09 12:10 AM
Joined: Aug 2007
Posts: 6,089
Valencia, España
NachoRT74 Offline
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NachoRT74  Offline
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Posts: 6,089
Valencia, España
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







and be sure about same block height on both sides!


With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Milling and big block cylinder heads... [Re: landon1] #341083
06/08/09 12:11 AM
06/08/09 12:11 AM
Joined: Oct 2004
Posts: 16,452
Canada
CrAzYMoPaRGuY Offline OP
I Live Here
CrAzYMoPaRGuY  Offline OP
I Live Here

Joined: Oct 2004
Posts: 16,452
Canada
Quote:

i heard 1" height were lower head bolts go....but when you're talking thousandths of an inch




Well, they are pretty well bang on at 1.00"
That being said, the TEXTURE of the head leaves me thinking somebody had a baddddd shift at Chrysler in the early 70's. It looks like the surface was prepped for a head gasket with 40 grit sandpaper!


CrAzYMoPaRGuY
Re: Milling and big block cylinder heads... [Re: NachoRT74] #341084
06/08/09 12:12 AM
06/08/09 12:12 AM
Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
1_WILD_RT Offline
Management Trainee
1_WILD_RT  Offline
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Posts: 27,347
Today? Who Knows?
Quote:

Quote:

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 ...




thats what made me choose some stuff "wrong"




Exactly, you believe what Chrysler put out not what some guy on Moparts with a negative outlook posts... Just cause he was right shouldn't have any bearing... Till you realise the reason he is so negative is he's BTDT & already paid those dues...

Re: Milling and big block cylinder heads... [Re: JohnRR] #341085
06/08/09 12:15 AM
06/08/09 12:15 AM
Joined: Oct 2004
Posts: 16,452
Canada
CrAzYMoPaRGuY Offline OP
I Live Here
CrAzYMoPaRGuY  Offline OP
I Live Here

Joined: Oct 2004
Posts: 16,452
Canada
Quote:



It is not surprising to see the intake side not cut , that cost EXTRA over the deck mill .




So if the heads have NOT been cut and I will now be using .040" Felpro head gaskets, and I cut the heads .030" I shouldn't have much of an issue.

If the heads HAVE been cut and I run a Felpro head gasket with an additional .030" cut I will have an issue, I assume, if the intake face hasn't been cut as well.

Lots of guys will cut the head .030" and use a Felpro gasket and NOT do the intake surface, which is what I thought *might* have been the case, but if the head isn't cut and just had an atrocious surface I might not want to touch the intake surface either.....

Anybody confused yet?


CrAzYMoPaRGuY
Re: Milling and big block cylinder heads... [Re: CrAzYMoPaRGuY] #341086
06/08/09 12:20 AM
06/08/09 12:20 AM
Joined: Jul 2008
Posts: 403
NE Ohio
7
71 FJ6 Charger Offline
mopar
71 FJ6 Charger  Offline
mopar
7

Joined: Jul 2008
Posts: 403
NE Ohio
"Exactly, you believe what Chrysler put out not what some guy on Moparts with a negative outlook posts... Just cause he was right shouldn't have any bearing... Till you realise the reason he is so negative is he's BTDT & already paid those dues... "

well put!


'71 383HP FJ6 Charger SE
Re: Milling and big block cylinder heads... [Re: 71 FJ6 Charger] #341087
06/08/09 12:23 AM
06/08/09 12:23 AM
Joined: Oct 2004
Posts: 16,452
Canada
CrAzYMoPaRGuY Offline OP
I Live Here
CrAzYMoPaRGuY  Offline OP
I Live Here

Joined: Oct 2004
Posts: 16,452
Canada
Quote:

"Exactly, you believe what Chrysler put out not what some guy on Moparts with a negative outlook posts... Just cause he was right shouldn't have any bearing... Till you realise the reason he is so negative is he's BTDT & already paid those dues... "

well put!





It would be interesting to tear down a Mopar, Ford and GM engine from the late 60's and see just how far off EVERYTHING printed in literature was back then, heads ccs, compression ratios, rocker ratios, horsepower outputs etc etc....


CrAzYMoPaRGuY
Re: Milling and big block cylinder heads... [Re: CrAzYMoPaRGuY] #341088
06/08/09 12:23 AM
06/08/09 12:23 AM
Joined: Jul 2008
Posts: 403
NE Ohio
7
71 FJ6 Charger Offline
mopar
71 FJ6 Charger  Offline
mopar
7

Joined: Jul 2008
Posts: 403
NE Ohio
Quote:

Quote:



It is not surprising to see the intake side not cut , that cost EXTRA over the deck mill .




So if the heads have NOT been cut and I will now be using .040" Felpro head gaskets, and I cut the heads .030" I shouldn't have much of an issue.




If the heads HAVE been cut and I run a Felpro head gasket with an additional .030" cut I will have an issue, I assume, if the intake face hasn't been cut as well.

Lots of guys will cut the head .030" and use a Felpro gasket and NOT do the intake surface, which is what I thought *might* have been the case, but if the head isn't cut and just had an atrocious surface I might not want to touch the intake surface either.....

Anybody confused yet?






Sounds like you need a set of heads...


'71 383HP FJ6 Charger SE
Re: Milling and big block cylinder heads... [Re: 71 FJ6 Charger] #341089
06/08/09 12:24 AM
06/08/09 12:24 AM
Joined: Oct 2004
Posts: 16,452
Canada
CrAzYMoPaRGuY Offline OP
I Live Here
CrAzYMoPaRGuY  Offline OP
I Live Here

Joined: Oct 2004
Posts: 16,452
Canada
Quote:

Quote:

Quote:



It is not surprising to see the intake side not cut , that cost EXTRA over the deck mill .




So if the heads have NOT been cut and I will now be using .040" Felpro head gaskets, and I cut the heads .030" I shouldn't have much of an issue.




If the heads HAVE been cut and I run a Felpro head gasket with an additional .030" cut I will have an issue, I assume, if the intake face hasn't been cut as well.

Lots of guys will cut the head .030" and use a Felpro gasket and NOT do the intake surface, which is what I thought *might* have been the case, but if the head isn't cut and just had an atrocious surface I might not want to touch the intake surface either.....

Anybody confused yet?






Sounds like you need a set of heads...





NEXT rebuild...

This one is getting the car running and driving...
(I hope!)


CrAzYMoPaRGuY
Re: Milling and big block cylinder heads... [Re: CrAzYMoPaRGuY] #341090
06/08/09 12:31 AM
06/08/09 12:31 AM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
R
RapidRobert Offline
Circle Track
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R

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Posts: 36,040
Lincoln Nebraska
Quote:

Anybody confused yet?



not yet. I'd mock it up & put the heads/gaskets on the block & barely snug them down with several bolts & check your intake port to head port alignment which is the most important thing to want to get right with this(along w CR & quench) & when its right the bolt holes will easily be in alignment and head gaskets only compress a couple of thou from new to torqued.


live every 24 hour block of time like it's your last day on earth
Re: Milling and big block cylinder heads... [Re: 1_WILD_RT] #341091
06/08/09 12:51 AM
06/08/09 12:51 AM
Joined: Aug 2007
Posts: 6,089
Valencia, España
NachoRT74 Offline
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NachoRT74  Offline
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Posts: 6,089
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Quote:

Till you realise the reason he is so negative is he's BTDT & already paid those dues...








whats BTDT ?

I don't get every abreviation yet!!!

Last edited by NachoRT74; 06/08/09 12:55 AM.

With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Milling and big block cylinder heads... [Re: CrAzYMoPaRGuY] #341092
06/08/09 12:53 AM
06/08/09 12:53 AM
Joined: Jan 2003
Posts: 74,905
U.S.S.A.
JohnRR Offline
I Win
JohnRR  Offline
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Quote:

Quote:

"Exactly, you believe what Chrysler put out not what some guy on Moparts with a negative outlook posts... Just cause he was right shouldn't have any bearing... Till you realise the reason he is so negative is he's BTDT & already paid those dues... "

well put!





It would be interesting to tear down a Mopar, Ford and GM engine from the late 60's and see just how far off EVERYTHING printed in literature was back then, heads ccs, compression ratios, rocker ratios, horsepower outputs etc etc....




I have , the 56K original mile 383 HP in my dart , it still has shim head gaskets with part number begining with 18 part number , the pistons are if i remember right .006 in the hole , should be .003 , I haven't cc'd a head yet ...

Re: Milling and big block cylinder heads... [Re: NachoRT74] #341093
06/08/09 01:00 AM
06/08/09 01:00 AM
Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
1_WILD_RT Offline
Management Trainee
1_WILD_RT  Offline
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Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
Quote:

Quote:

Till you realise the reason he is so negative is he's BTDT & already paid those dues...








whats BTDT ?

I don't get every abreviation yet!!!




Been There.. Done That...

Re: Milling and big block cylinder heads... [Re: JohnRR] #341094
06/08/09 01:04 AM
06/08/09 01:04 AM
Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
1_WILD_RT Offline
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1_WILD_RT  Offline
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Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
Quote:


I have , the 56K original mile 383 HP in my dart , it still has shim head gaskets with part number begining with 18 part number , the pistons are if i remember right .006 in the hole , should be .003 , I haven't cc'd a head yet ...




So you'll telling me they only missed by .003... That would be exceptionally close to spec... Are you sure you didn't add a zero??? Cause .030 wouldn't really surprise me... .080 wouldn't eiither...

Re: Milling and big block cylinder heads... [Re: CrAzYMoPaRGuY] #341095
06/08/09 08:00 AM
06/08/09 08:00 AM
Joined: Aug 2005
Posts: 4,799
ILL
M
MLR426 Offline
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M

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ILL
Quote:

Quote:

i heard 1" height were lower head bolts go....but when you're talking thousandths of an inch




Well, they are pretty well bang on at 1.00"
That being said, the TEXTURE of the head leaves me thinking somebody had a baddddd shift at Chrysler in the early 70's. It looks like the surface was prepped for a head gasket with 40 grit sandpaper!




Sounds like heads were surfaced on a Platen Belt
surfacer. Many shops have platen surfacers for exhaust manifolds,oil pans, water pump housings etc. But many shops have platen surfacers and use them for surfacing heads. A good shop will have a CBN surfacing machine that uses a Cubic Boron Nitride 1/2" or 3/8" surfacing button for cast iron heads and blocks and PCD buttons Polycrystalite Diamond for all aluminum heads and blocks. These machines will give you the RMS surface finish you should have when using todays head gaskets especially with aluminum heads.

logan426

Last edited by Logan426; 06/08/09 11:39 AM.
Re: Milling and big block cylinder heads... [Re: 1_WILD_RT] #341096
06/08/09 09:00 AM
06/08/09 09:00 AM
Joined: Jan 2003
Posts: 74,905
U.S.S.A.
JohnRR Offline
I Win
JohnRR  Offline
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Posts: 74,905
U.S.S.A.
Quote:

Quote:


I have , the 56K original mile 383 HP in my dart , it still has shim head gaskets with part number begining with 18 part number , the pistons are if i remember right .006 in the hole , should be .003 , I haven't cc'd a head yet ...




So you'll telling me they only missed by .003... That would be exceptionally close to spec... Are you sure you didn't add a zero??? Cause .030 wouldn't really surprise me... .080 wouldn't eiither...




nope it's that close , I keep hearing of these MYTHICAL blocks that are .020 or MORE than factory spec but I haven't come across one yet , maybe I'm just lucky , I have another 69 383 HP I just picked up , rering/rebearing rebuild , original pistons , guess what ...

I put these TALLER than spec blocks right up their with UNICORNS ...

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