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if the post-Extrude Hone manifolds are still off the engine and available,
perhaps it would be a good idea to make some templates of the port shapes the EH process created?

if these templates were then scanned and added to the archives,
perhaps other factory manifold owners using a grinder could be very close to the gains found?

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I think I picked up a total of 12HP on a "back to back" test. That was on a 12 to 1, 484 cubed Hemi... making Huge power .

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There; I fixed that for you.



Dave

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Doug Dutra cast some new split /6 exhaust manifolds from scratch. For that kind of money a person could almost recast a set with a bigger ID. Just thinking out loud

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Well, I don't know if that would work or not, but let's say for a minute that it would, if you can get a set of (outwardly accurate, internally larger) exhaust manifolds cast for $600.00 please sign me up!

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As far as Dudeks Hemi picking up 12HP, I have no doubt that he did, as I said above:

I think there is a limit to gains you can expect but IMO every engine will benifit differently from it. As I've said before, you chase the bottle necks in the combo, if the bottleneck is the manifolds it will make a bigger difference and push the bottle neck to some other area needing improvment to gain more HP.

His combo obviously needed more exhaust flow and the EH process helped his engine in that respect more than it helped mine.

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Could be Dave, pure guesswork at this point.

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