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Old 07-31-2014, 04:51 AM
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6.4 exhaust manifold impulse buy

For about the last month I've been obsessing over the need for headers on my 2010 5.7 and in the wee hours of the morning (working graveyard shift this week) I stumbled over a pair of "6.4 stock exhaust manifolds" on ebay by a company called rubitrux. They claimed they were off of a 6.4 crate engine that had zero miles on it and I got them for $200. As impossible as these things are to find (except brand new direct from mopar for >$500 per manifold!!!) I jumped on it.

Someone fix me if I'm wrong here, but the manifolds for the 6.1 and 6.4 are the same, right? I don't need to grind any pesky holes for the EGR valve port? Just some slight grinding on the passenger side trans housing? Either way, the 6.4 Apache and the 5.7 Eagle heads have the same exhaust ports and bolt pattern. Right? Or did I just order myself a pair of $200 paper weights...
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Old 07-31-2014, 05:23 AM
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6.4 are the same bolt pattern and exhaust ports as the 6.1. I personally haven't read about someone going with a 6.4 header on a 5.7 but there are plenty who put 6.1s on. So you should be good. Keep us updating since it seems your the genie pig and might provide another option to us with 5.7s! Best of luck!

Btw If your required to keep your egr then you have to grind out a big enough dip for it so it can flow through. There are pictures about it on this forum if you dig a little.
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Old 07-31-2014, 06:00 AM
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Re: 6.4 exhaust manifold impulse buy

I'm stationed in the Communist state of NY so the EGR delete isn't really an option, looks like I'll be doing some grinding. Also worried about those O2 sensors codes, we'll see what the exhaust shop has to say once the manifolds get here in about a week.

Does anyone know of a schematic or some sort of diagram for the 5.7 exhaust system (showing location of cats relative to engine, O2 sensor locations, reducers and pipe diameter)? I had found one for my 4.7 WJ two years ago and it made the explanation/planning of what I wanted with the exhaust shop very helpful. I'm not 100% clear on the differences between the 6.1/4 and the 5.7 exhaust system other than "you have to grind an EGR notch in the passenger head, you have to grind the trans on the passenger side, you need O2 sensor re-locators/wire extensions"
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Old 07-31-2014, 05:57 PM
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Talking Re: 6.4 exhaust manifold impulse buy

Well, Rubitrux was nice enough to let me know at the close of business today that they "sold their stock much faster than expected" and were unable to provide me with manifolds. Which one of you @#$%&! beat me to the punch??? I asked Rubitrux to put me on a waiting list for either the 6.4 or 6.1 manifolds if/when they pop back up again.

Thanks for the confirmation that the head bolts and exhaust ports match up for 6.4 and 6.1 retrofits onto an Eagle 5.7 head. Does anyone know if the design/shape of the manifolds are any different between the 6.1 and 6.4? More importantly...

Does anyone have a set of either one laying around they're looking to sell?
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Old 08-07-2014, 09:56 AM
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Re: 6.4 exhaust manifold impulse buy

I was able to find a pair of 6.1 exhaust manifold take offs from Modern Muscle out of Virginia. Cost me about $500 including shipping (to upstate NY) which is not bad IMO for how hard it is to find the specific Jeep srt8 manifold and considering these cost around $1.1K brand new from the dealer.

Took the jeep to my local exhaust shop today for a planning/design session. After months of researching other forums and similar builds we are planning on chopping about 6" or so off of the top of the stock midpipes (y pipe) and fabricating flanges onto them that will fit the 6.1 manifolds. The plan is to weld new O2 bungs into these fabricated flanges at the top of the midpipes. Either that, or put them into the ends of the manifolds themselves as they are about 6" longer than the stock manifolds and that is roughly where the upstream o2 sensors are now. The hard part is going to be welding onto/altering these midpipes as they taper out wider into dual walled pipes and back into single wall pipes at the connection points (flange, just upstream and just downstream of each cat). The weird part is that the two downstream o2 sensors seem to be in the middle of the cats. Worst comes to worst we'll just chop the cats out and weld them into fabricated shop pipes. I'd love to use high flow cats but I'm too worried about throwing 02 sensor codes and there needs to be SOME amount of back pressure for proper engine performance.
Finally laid eyes on the little piece of transmission housing on the passenger side that gets in the way of the 6.1 manifold, it's a connection piece that the Ram trucks use (my mechanic is a Ram guy) and won't be an issue to chop it off. I was quoted at about $900 which seems on par with the complexity of the work and what I've seen charged for similar jobs on multiple forums.
We're going to pull the trigger and start chopping into it within the next two weeks.n Any and all help/suggestions on this project would be greatly appreciated!
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