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  #1  
Old 02-10-2000, 03:33 AM
nothingbutmopars nothingbutmopars is offline
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Join Date: Jan 2000
Location: cole camp, Mo
Age: 68
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Question

I have a '65 426 street wedge with '74 400/440 heads. Are these a better head than the original heads? I know the exhaust valves are bigger in the '74 heads but what is the difference between the combustion chamber? Bottom line,will there be an improvement in performancs with the '74 heads or was the change probably made for the hardened seats/unleaded gas and the wider selection of intakes that would work with the '74 heads opposed to the original heads?
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'71 Challenger R/T
'70 Road Runner 440+6
'70 Super Bee
'69 Super Bee
'69 Charger
'68 Road Runner
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Old 02-10-2000, 11:55 AM
DartGT66 DartGT66 is offline
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Join Date: Sep 1999
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The 426 original heads are closed chamber heads, and the '68 & up heads are open chamber with about 10 cc bigger chambers. Therefore, if the heads have not been milled you have lost some CR. If the compression ratios are equal, the newer heads will delivery noticably better performance, they have better flowing ports and bigger exhaust valves. The intakes and exhausts are a bolt on.
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