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06-29-2008, 11:26 PM
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#1 |
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Registered User
Join Date: Feb 2008
Location: Johnson City Tennessee
Posts: 1,176
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pistons
first on pistons wich is better a 4 valve release flat top or a valve release flat top is there any diffrence if so what? is there a compression ratio diffrence and is there a power diffrence?
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Greater love hath no man than to lay down his life for a friend. Members i Have met Earl Slick68 1969 Stepside Build thread http://67-72chevytrucks.com/vboard/s...=1#post4253546  Chevy Trucks the longest lasting most dependable trucks on the road
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06-30-2008, 03:09 AM
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#2 |
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Long Fleet Club
Join Date: Aug 2006
Location: Deer Park, TX
Posts: 5,666
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Re: pistons
If you are talking about the difference in compression ratio between the two flat top pistons then there will be a very small compression ratio difference but not enough to notice and no power difference.
About the valve reliefs then Omnivec is right.
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Chris Meeks '69 Chevy Custom/10 Long Bed <-- Thread of the work I did before selling. Truck is now finished to the new owners design and running around. I was shown some pictures of the finished product. At least it survived the junk yard. FAQ Index by Krue Site Vendors Subscribe Here Forum Rules Last edited by cameeks; 06-30-2008 at 01:52 PM. Reason: Posting when I was asleeep :) |
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06-30-2008, 08:53 AM
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#3 |
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Registered User
Join Date: May 2007
Location: CA
Posts: 39
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Re: pistons
The reason small blocks use 4 valve reliefs is so they can be used in ether bank of a engine. It is usually for more economical pistons. If its a stock piston with 2 valve reliefs its probably out a High hp engine. The Flat tops well give more power and probable about .5 to 1.0 bump in compression.
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67 3/4 Lwb Step side X San Diego County truck 70 3/4 berb was 402 Th400 Dana 60 now just the dana 70 3/4 lwb Fleet Choptop bagged th350 no eng yet 79 rx7 Wide body 350 TPI t5 flat black(The interceptor) 64 comet mounted on a 93 Thunderbird chassis. |
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07-09-2008, 01:38 AM
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#4 |
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Registered User
Join Date: Feb 2008
Location: Johnson City Tennessee
Posts: 1,176
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Re: pistons
so are the 4 valve release better than a 2 release piston?
__________________
Greater love hath no man than to lay down his life for a friend. Members i Have met Earl Slick68 1969 Stepside Build thread http://67-72chevytrucks.com/vboard/s...=1#post4253546 Chevy Trucks the longest lasting most dependable trucks on the road
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07-09-2008, 02:59 AM
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#5 |
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Long Fleet Club
Join Date: Aug 2006
Location: Deer Park, TX
Posts: 5,666
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Re: pistons
Are you comparing flat top to fat top? The valve reliefs don't mean that it is a better piston. The material that it is made of does. You can get a cheap piston that has 2 reliefs in it. If it is aftermarket then it would be stamped with the manufactures name and probably model number.
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Chris Meeks '69 Chevy Custom/10 Long Bed <-- Thread of the work I did before selling. Truck is now finished to the new owners design and running around. I was shown some pictures of the finished product. At least it survived the junk yard. FAQ Index by Krue Site Vendors Subscribe Here Forum Rules |
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07-09-2008, 09:25 AM
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#6 |
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Account Suspended
Join Date: Sep 2005
Location: Monroe, WA
Posts: 3,815
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Re: pistons
You're maybe getting a little hung up on the relief thing
 Omnivec nailed it - it's just a manufacturing shortcut so the pistons can be used in either bank. Although it has nothing specifically to do with the quality of the piston, typically the "rebuilder" pistons are 4-relief.In terms of CR, 2 reliefs are generally around -5cc volume; doubling that to -10cc can mean about a .5 drop in CR. Even flat-top pistons will likely have valve reliefs. |
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