72' 340 Drivers side HP manifold vs older HP manifold

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In the picture (above) you can see a hump on the downward sweep of the late 340 (background) while the early 340 is virtually flat.




In the next 2 pic you can easily see that the early 340 is taller with respect to the exhaust ports:

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In this last pic you can see that the early 340 rises higher (vertically) than the late 340:

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Doesn't it depend on RPM??? From what I have read and experienced headers are great for performance at the higher RPMs (5500 and up). But at the lower RPMs a good set of 340 manifolds don't really hurt your engine performance more than 3-4 percent. As far as the difference in the early 340 VS the newer....they are virtually the same as far as flow is concerned. They are designed differently in that the early manifold rises higher in relation to the exhaust ports. The early manifold also seems to "hug" the engine a little tighter, for these reasons the early manifolds fit better on the early As than the older 340 manifolds. Unfortunately the early manifolds are usually more expensive and harder to find because there were very few made.View attachment 1714947141 View attachment 1714947142 View attachment 1714947143 View attachment 1714947144

Treblig
Thanks for the great reply treblig. I'm generally not a fan of headers for all the reasons you mentioned which is why I'm asking all these questions to begin with. So what I'm hearing is that manifolds for the most part are going to perform we'll with the the exception of perhaps higher rpm use which all be it fun, is not the range we mostly drive in anyway.
Did you mean to say that the early manifolds hug and fit better that the later manifolds? If you re read that section it says early fits better than 'older'?

I'm contemplating these so I can put on normal exhaust and also get the ride height back to more of a normal stance on the car. I just got the car and this is how the previous owner had it all set up.

Thanks so much!

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