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440 Compression Ratio Advice
#1150562
01/04/12 10:15 PM
01/04/12 10:15 PM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
OP
top fuel
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OP
top fuel
Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
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I am building a stockish 440. The .030 over flat top pistons are .085 in the hole. The cam I'm using calls for minimum 9.5:1 compression. I'm on a budget and having a difficult time finding affordable heads to get me there. I was going to order the reman Aerohead 915s with 78cc chambers which would get me around 9.6:1 with .020 steel shim gaskets. Perfect, but since I figured my budget, the price has gone up on them and with shipping, they will be almost $900 for the set. Too much in my opinion for stock cast iron heads. My next thought was the 440 Source Stealths for about $180 more. A no-brainer right? Except the chambers on those are 80cc(+-) and I have to use the .040 composite head gaskets. That will get me 9.24:1 compression. Not far off, but under the minimum. And I really don't want to go through the added expense of tearing them apart and having them cut. Now for the question...will this be a significant/noticeable difference? Opinions? Thanks!! 
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Re: 440 Compression Ratio Advice
[Re: 05dakota]
#1150566
01/04/12 10:46 PM
01/04/12 10:46 PM
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Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
torkrules
I'm neurotic
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I'm neurotic
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
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Quote:
different pistons?
If you can, I would go for zero deck height and use a .040" gasket. This will give you good fuel mixing. With an aluminum head (something like a small chamber Edelbrock) and zero deck height you can run around 10.0 comp and not run into detonation problems on pump gas.
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Re: 440 Compression Ratio Advice
[Re: BSB67]
#1150569
01/05/12 01:16 AM
01/05/12 01:16 AM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
OP
top fuel
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OP
top fuel
Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
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Quote:
This is the classic delimma of the low-buck short block. It appears that you have correctly figured it out, you have no good low cost choice. It will probably cost $2000 to make it right. Everything else will be a compromise. If you have the money for the Stealths, that is probably your most practical compromise. Some people run a shim gasket with them successfully.
How do you think it will run with the 9.24:1 with that cam? I asked at 440 Source and he said definitely not to use the steel shim gaskets. Also that the difference in compression wouldn't be noticeable and would be ok to run as is...but I would think they advertise a minimum for a reason??
Cam Specs:
Summit SUM-6401 cam.
Which states min. 9.5:1 compression.
int .465
exh .488
adv dur. .282 int/.292exh
int. dur @ .050 .224
exh. dur @ .050 .234
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Re: 440 Compression Ratio Advice
[Re: bobs66440]
#1150570
01/05/12 02:02 AM
01/05/12 02:02 AM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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Many on here have run aluminum heads with the steel shim gasket. They spray the gasket on both sides with permatex copper coat and you're good to go.
FWIW, the summit cam you have listed there is not that aggressive of a cam. You can easily run that cam with 9.2 compression. I ran more cam in a smogger 440 with an actual calculated 8:1 compression and it did okay. Also, the .4 of compression difference between the two sets of heads you are thinking about, will not be noticeable on your combo. My brother has a 66 charger with a 440, stock heads, same 6401 cam and probably about the same compression as you're shooting for and it runs well.
Another option is to see if someone is selling a used set of closed chambered iron heads in the for sale section here on moparts. Sometimes there are good deals to be had, however the stealth heads will flow better OOTB than those stockers.
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Re: 440 Compression Ratio Advice
[Re: DaytonaTurbo]
#1150571
01/05/12 03:10 AM
01/05/12 03:10 AM
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Joined: Jun 2006
Posts: 5,163
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,163
CT
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Don't worry about it, just put the cam in and run it. You won't notice the difference.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: 440 Compression Ratio Advice
[Re: DaytonaTurbo]
#1150574
01/05/12 08:27 AM
01/05/12 08:27 AM
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Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
torkrules
I'm neurotic
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I'm neurotic
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
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Quote:
Many on here have run aluminum heads with the steel shim gasket. They spray the gasket on both sides with permatex copper coat and you're good to go.
FWIW, the summit cam you have listed there is not that aggressive of a cam. You can easily run that cam with 9.2 compression. I ran more cam in a smogger 440 with an actual calculated 8:1 compression and it did okay. Also, the .4 of compression difference between the two sets of heads you are thinking about, will not be noticeable on your combo. My brother has a 66 charger with a 440, stock heads, same 6401 cam and probably about the same compression as you're shooting for and it runs well.
Another option is to see if someone is selling a used set of closed chambered iron heads in the for sale section here on moparts. Sometimes there are good deals to be had, however the stealth heads will flow better OOTB than those stockers.
You can always use Cometics. They make a .027 thick gasket if needed.
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Re: 440 Compression Ratio Advice
[Re: bobs66440]
#1150575
01/05/12 09:08 AM
01/05/12 09:08 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Quote:
This is the classic delimma of the low-buck short block. It appears that you have correctly figured it out, you have no good low cost choice. It will probably cost $2000 to make it right. Everything else will be a compromise. If you have the money for the Stealths, that is probably your most practical compromise. Some people run a shim gasket with them successfully.
How do you think it will run with the 9.24:1 with that cam? I asked at 440 Source and he said definitely not to use the steel shim gaskets. Also that the difference in compression wouldn't be noticeable and would be ok to run as is...but I would think they advertise a minimum for a reason??
Cam Specs:
Summit SUM-6401 cam.
Which states min. 9.5:1 compression.
int .465
exh .488
adv dur. .282 int/.292exh
int. dur @ .050 .224
exh. dur @ .050 .234
I ran 12.90's @ 104 with the same cam in a MAYBE 9:1(stock speed pro replacements) 440, RPM intake Holley 750DP, non-ported 906 heads, 1 3/4 headers, same 175k convert, and 3.91 all packed into a nice light (3850) 67 coronet. I wouldn't worry too much about it. If you go w/ the stealths you always have room to grow.
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Re: 440 Compression Ratio Advice
[Re: torkrules]
#1150576
01/05/12 09:21 AM
01/05/12 09:21 AM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
OP
top fuel
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OP
top fuel
Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
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Ok guys, Thanks for the replies! Sounds like the Stealths are the way to go. I appreciate it! Quote:
Quote:
Many on here have run aluminum heads with the steel shim gasket. They spray the gasket on both sides with permatex copper coat and you're good to go.
FWIW, the summit cam you have listed there is not that aggressive of a cam. You can easily run that cam with 9.2 compression. I ran more cam in a smogger 440 with an actual calculated 8:1 compression and it did okay. Also, the .4 of compression difference between the two sets of heads you are thinking about, will not be noticeable on your combo. My brother has a 66 charger with a 440, stock heads, same 6401 cam and probably about the same compression as you're shooting for and it runs well.
Another option is to see if someone is selling a used set of closed chambered iron heads in the for sale section here on moparts. Sometimes there are good deals to be had, however the stealth heads will flow better OOTB than those stockers.
You can always use Cometics. They make a .027 thick gasket if needed.
I was on their site and all I see is .040 gaskets. Are the .027 ones custom?
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Re: 440 Compression Ratio Advice
[Re: bobs66440]
#1150577
01/05/12 11:44 AM
01/05/12 11:44 AM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
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Quote:
Ok guys, Thanks for the replies! Sounds like the Stealths are the way to go. I appreciate it!
Quote:
Quote:
Many on here have run aluminum heads with the steel shim gasket. They spray the gasket on both sides with permatex copper coat and you're good to go.
FWIW, the summit cam you have listed there is not that aggressive of a cam. You can easily run that cam with 9.2 compression. I ran more cam in a smogger 440 with an actual calculated 8:1 compression and it did okay. Also, the .4 of compression difference between the two sets of heads you are thinking about, will not be noticeable on your combo. My brother has a 66 charger with a 440, stock heads, same 6401 cam and probably about the same compression as you're shooting for and it runs well.
Another option is to see if someone is selling a used set of closed chambered iron heads in the for sale section here on moparts. Sometimes there are good deals to be had, however the stealth heads will flow better OOTB than those stockers.
You can always use Cometics. They make a .027 thick gasket if needed.
I was on their site and all I see is .040 gaskets. Are the .027 ones custom?
The cometics are very expensive, run the .040 gasket that the source recommends.
Also plan on having the heads disassembled and the valve job checked and also check the retainers and locks. Have the chambers CC'sd also, they may be a little bigger than advertised.
I ran that cam ain an advertised 9.2 compression 383that had 130k miles on it , probably more like 8.0 , and it ran well.
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Re: 440 Compression Ratio Advice
[Re: bobs66440]
#1150579
01/05/12 01:16 PM
01/05/12 01:16 PM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
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Quote:
Are there quality issues with the 440 Source heads?
Can't say either way but EVERY thing you buy needs to be checked , NOTHING is ready to run out of the box.
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Re: 440 Compression Ratio Advice
[Re: Mr.Yuck]
#1150581
01/05/12 02:38 PM
01/05/12 02:38 PM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
OP
top fuel
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OP
top fuel
Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
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I have been watching the ads and there's really not too much...that's affordable anyway. I have a set of 906 heads that need to be completely gone through but they are, what, like 85-90cc or so? That will put my compression way down in the basement. Then I would have to go with another cam or pistons. The Aeroheads were really the perfect solution because they are 78cc, but the price with shipping ended up in the same price range as aluminum heads. I priced out rebuilding my heads locally and it's a little cheaper, but I still have the compression issue. The engine in the car now is a stock (I believe) '66 440 from a Imperial or similar. I'm not sure what heads are on that but they are in worse condition than my 906s...I suppose I could pull the valve cover and at least see what they are....and keep looking in the ads. BTW Mr. Yuck, I saw your car in Car Craft (I think it was anyway). Very cool!
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