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Question on speedmaster heads

MerlinsMopars

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I want to get a set of these heads for my 340 so I can run unleaded. They are the loaded ones for $1015.00 at jegs but they are saying something about raised exhaust ports and I have the dougs d453 headers. Are these headers going to work with these heads? Going in my 71 challenger.
Any setbacks that I need to look out for?
Thanks,
Scott
 

1972CudaV21

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If you‘re just concerned about using unleaded gas, the valve seat lubrication is rarely an issue.
 

MerlinsMopars

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If you‘re just concerned about using unleaded gas, the valve seat lubrication is rarely an issue.
My x heads are unusable because of using unleaded. The valve seats are beat up in the heads and machine shop says thats why.
 

Steve340

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Can you find out how much the port is raised? If it is only a small amount you might be OK??
 

Steve340

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That is quite a bit. Off the top of my head that could cause problems.
Never used those heads though.
 
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