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Joined: Mar 2004
Posts: 115
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Member
Joined: Mar 2004
Posts: 115 |
I what kind of compression ration am I looking at with at 455 std bore, flat top pistons with valve relief if I use the 6x-8's vs the 7M5's. I only ask because the 7m5's are already in my possession and the 6x-8's would have to be purchased. Any ideas? I'm looking for a very mild build that will have nitrous. Thoughts?
1969 6.0 Firebird: project started (2/19/2014 LQ9 and 4L80E on the way)
Information overload mode on this build
2013 Chevy Volt/2005 Ford F350 6.0 PSD CC 4x4 Lariat/2008 Honda Gold Wing
Looking for 68-72 A body Wagon, prefer 70 Chevelle Wagon
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Joined: Aug 2002
Posts: 7,495 Likes: 1
Premium Member
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Premium Member
Joined: Aug 2002
Posts: 7,495 Likes: 1 |
Run your numbers on one of the ratio calculators. Don't forget the head gasket thickness. Felpro's run about .042-.045. And valve reliefs are 6-7cc.
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Joined: Apr 2000
Posts: 7,408
Power Member
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Power Member
Joined: Apr 2000
Posts: 7,408 |
Should be around 8.1.
To make it worthwhile, 9 to 9.5 is preferred to make building the motor worth the expense.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto
1968 Alpine Blue 400 4 speed
1968 Verdoro Green 400 HO 4 speed
2013 1LE 2SS/RS Inferno Orange Camaro.
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Joined: Apr 2000
Posts: 7,408
Power Member
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Power Member
Joined: Apr 2000
Posts: 7,408 |
Would go with a pair of 96's or 6X-4
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto
1968 Alpine Blue 400 4 speed
1968 Verdoro Green 400 HO 4 speed
2013 1LE 2SS/RS Inferno Orange Camaro.
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Joined: Mar 2004
Posts: 115
Member
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Member
Joined: Mar 2004
Posts: 115 |
Thanks for the info. Looks like the 7M5's are only going to give about 7.3/7.4:1. Ordered a set of 96's from Pontiac Dude. Should give me +- 9.1:1.
1969 6.0 Firebird: project started (2/19/2014 LQ9 and 4L80E on the way)
Information overload mode on this build
2013 Chevy Volt/2005 Ford F350 6.0 PSD CC 4x4 Lariat/2008 Honda Gold Wing
Looking for 68-72 A body Wagon, prefer 70 Chevelle Wagon
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