Exhaust manifold option

[Elevated 2013]

Hey all! I had some interesting information come my way tonight. After finding out and doing some research, I found out that the 6.4l exhaust manifold will bolt onto the 5.7l engines. What I need to know now is if anyone has tried to install the 6.4l exhaust manifold into a 5.7l 1500? I’m wondering if it will fit as well as if it bolts up to the stock y pipe? Any help/experience tips are appreciated! I’m looking at the JEEP Grand Cherokee SRT8 exhaust manifolds from 2013 and newer.

 

[Elevated 2013]

I did some more research and TruckTrend.com put a Hellcat engine into a 2017 1500 and used a 2010 Grand Cherokee SRT8 exhaust manifold set. Since the blocks are similar or basically the exact same, I don’t see any reason they shouldn’t fit with a 5.7 and flow better. Agreed??

 

[Wild one]

I've never done the SRT Jeep 6.4 manifold swap on a truck,but a few guys have,and supposedly they'll fit with a bit of exhaust tweaking.I know putting the 6.4 manifolds on my wifes 5.7 Challenger made a difference.The stock manifolds off her 5.7 car didn't really look all that different from the stock manifolds on my truck,small ports and not a great flow path to the collector,so i'd hazard a guess if you find a set of 6.4 Jeep manifolds cheap enough,they'll be a worth while upgrade. We swapped the stock 2.75" diameter 6.4 midpipes onto my wifes "untuned" 2016 5.7 Challenger and just reused the cars original 02's and it hasn't set any codes since I did the swap and that's about a 1,000 miles ago now. Her car also has a 180 t-stat /Legmaker carbon fibre intake tube /Hellcat headlight duct kit plus a resonator delete kit,and it picked up a noticeable amount of power with the free'r flowing 6.4 manifolds.

 

[Elevated 2013]

It looks and sounds like it will fit but the y pipe will need some massaging some how from what I gather or I’d have to figure out how to make the intermediate pipe and muffler meet it because that y pipe isn’t going to have any real wiggle room to move.

 

[Hemi395]

From the pics I've seen of both manifolds it looks like the collector flanges are different angles? I was actually considering these manifolds but then found a killer deal on a used set of JBA shorties....

 

[Elevated 2013]

From the pics I've seen of both manifolds it looks like the collector flanges are different angles? I was actually considering these manifolds but then found a killer deal on a used set of JBA shorties....

I think you’re right about the collectors and I know the manifolds go out a little farther than the 5.7 manifolds. What I’m wondering is if the difference in the distance away from the block and the difference of the angles almost make up for the change. I’m trying to see if I can get my hands on a manifold and see what the actual differences are to see what manipulations would need to be done to the y pipe or intermediate pipe to make them work or if they’re just too different.

 

[Wild one]

I think you’re right about the collectors and I know the manifolds go out a little farther than the 5.7 manifolds. What I’m wondering is if the difference in the distance away from the block and the difference of the angles almost make up for the change. I’m trying to see if I can get my hands on a manifold and see what the actual differences are to see what manipulations would need to be done to the y pipe or intermediate pipe to make them work or if they’re just too different.

I've never heard of anybody trying the 6.4 car manifolds out,but after putting a set on the boss's car,i almost wonder if they might fit the trucks,i still think you'd need a little bit of mid pipe tweaking though if they did fit.

 

[Elevated 2013]

I agree. I was looking at the Jeep Grand Cherokee SRT manifolds that only Jeep makes as nobody else in the aftermarket world makes them. I’m hoping a scrap yard might have 1 that I can look at to see what all of the differences are. If they worked well on the Hellcat motor in a Ram 1500, I don’t see why they wouldn’t flow well for a 5.7.