And they make little difference unless you wind the crap out of the engine
Edelbrock heads with OEM manifolds
- Thread starter Kenflo
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And they make little difference unless you wind the crap out of the engine
That’s engine build specific and…. LOL…..
Depends on your opinion of “The in’s the crap out of the engine.”
That’s starts at 7K for me….. but that’s just me…..
Depends on your opinion of “The in’s the crap out of the engine.”
That’s starts at 7K for me….. but that’s just me…..
Well, I'm gonna have to disagree with that. Headers don't just add power up top, they add a bunch of torque; they help a lot everywhere. The difference was amazing to me.
Agree there. I was talking about the 340 stock manifolds. May have got out of sync with the thread.
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OK, gotcha!
Now if only someone would make one for a slant six.
1WildRT
Well-Known Member
So, first, the grind on the head method...Some have done it & gotten away with it.... Some like Steve Dulcich have found water.... What I did was use an old header flange as a spacer.... Moved the manifold out about 5/16" giving about 1/8" clearance..
340six
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I ended up doing a slight blend at the sharp edge.
And then ground the exhaust. I blended the ports (port matched) had a friend's shop surface them, so they would be square and flat. They need to be ground from cut from the millling mark down. I did so little at a time untill I had clearance but used header gaskets between the heads-manifolds.
And then ground the exhaust. I blended the ports (port matched) had a friend's shop surface them, so they would be square and flat. They need to be ground from cut from the millling mark down. I did so little at a time untill I had clearance but used header gaskets between the heads-manifolds.
340six
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I agree with this all I did was take the hard square edge off. I Was Scared of Water. Was better to remove it from the manifold and use thick gaskets.
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I don't believe Edelbrock (or anyone else for that matter) made aluminum heads with the thought that anyone would ever run exhaust manifolds on them.
Probably true, but my 340's power noticeably improved just swapping from OEM to Edelbrock heads on my 340, while keeping the stock exhaust manifolds. Of course, it runs better now that it has headers.
I have run thousands of models on Performance Trends software and it is clear the thing that makes power in order of importance are
1) Head and valve flow
2) Headers
Where you want make that power in the RPM range and how good of head/valve flows you have defines what camshaft you use and from that you derive the compression ratio.
Have used that formula on all my builds
1) Head and valve flow
2) Headers
Where you want make that power in the RPM range and how good of head/valve flows you have defines what camshaft you use and from that you derive the compression ratio.
Have used that formula on all my builds
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If you decide to keep the headers but need the reduced heat running electric fans a can help a lot if you are driving in traffic.
I haven't tried it but running a thicker remflex gasket or even doubling gaskets on that side may work.
IMO, knowing what I now know thanks to those experienced with this endeavor and as expensive as heads, headers and even factory 340 exhaust manifolds are anymore I'd lean more towards either spacing the stock manifolds out or headers.
I personally wouldn’t try double exhaust gaskets. It may hold, but I’m not too warm and fuzzy on the idea. Worth a shot!
I second that. Even on a very mild cam and compression engine, it’s a winner.
70Duster340
Well-Known Member
I can tell you it won't fit. Been there, done that. Because of the shape of the manifold, it hits the head where the manifold curls under. I tried removing some of the manifold material, but too much material needed to be removed for my comfort. I got a header flange to act as a spacer. You'll have to use 2 gaskets, 1 between the flange and the head and 1 between the manifold and the flange. There's probably a better way, but that's how I solved it. I did speak with a tech from Edelbrock, but they couldn't offer a solution.
MopaR&D
Nerd Member
I've also had similar experience, the 5.9/360 in my Duster has ported Edelbrocks and 9:1 compression while the 360 in my D200 has stock iron heads and 8:1 compression (rated 8.2:1 but likely lower). I've never had the Duster engine ping even when the ignition timing was overly advanced but the truck engine pings like a SOB especially in hot weather if it has just a little bit too much advance.
To add to the OP's original question, I've had issues with an early 340 driver side manifold interfering with a factory Magnum head in that same location as the Edelbrocks.
Professor Fate
Push the button, Max...
I've noticed the Magnum interference, too. It's not as major of an interference, but it's there. I'm sure it varies due to manufacturing tolerances, but in my situation a thick gasket cleared it up, didn't have to resort to the header flange fix in that case.
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