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JS1977

392/6.4 Intake Manifold On A 5.7

61 posts in this topic

It would be cool to see a dyno run after this was done. I've heard of the gens before us actually losing power switching to the 6.1 manifold. Whats the material the 392 manifold is made from?

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Hey! That was off my car. I'd recognize that packaging anywhere. There's a lot of good mojo in that intake! :)

 

IMG_2043_zps83b4a761.jpg

Where could I get the same intake and fuel rail? How much did you pay for it? Also will the 5.7 throttle body work or did you have to use the 6.4 throttle body? I am installing a 2010 5.7 off a dodge ram in a 1972 dodge dart but the intake will not fit I need one that has a 45 angle like the 6.4.

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Where could I get the same intake and fuel rail? How much did you pay for it? Also will the 5.7 throttle body work or did you have to use the 6.4 throttle body? I am installing a 2010 5.7 off a dodge ram in a 1972 dodge dart but the intake will not fit I need one that has a 45 angle like the 6.4.

Pm sent I have one for sale

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Has anyone else added this mod and then hit a dyno?  I added a Jay Green cam and PnP heads with mine and my top end is much stronger.  It no longer drops off like it did prior.  My switch is set to activate the short runners at 4800 but I see no visible changes in the dyno.  I don't know if it's taken out with the smoothing or if it's not opening and I'm stuck in long runner.  

 

I dyno'd prior to my mods but it was at a different dyno.  I can only really compare the power curve between the two.  However, I add that my buddy dyno'd exactly both days so I can use him as a bit of a ref:
 

                dyno 1 (before my mods)   dyno 2

Me           374/401                             381/399

Buddy      376/405                             330/360      - The power curve was the same but the dyno was roughly 12% lower.

 

Low - Very similar results:  This leads me to theorize that the long runners possibly helped offset any loss from the larger cam.

          New dyno starts at 3k RPM / 195 hp - by 4k RPM, it appears to be slightly ahead of old dyno

          Old dyno starts at 3k RPM / 205 hp - by 4k RPM, it appears to be slightly lower than new dyno

Mid - Very similar results:

         New dyno from 4.3K to 5K both are around 380 ft lbs and by 5250 I'm down to 375.  

         Old dyno from  4.3K to  5K both are around 380 ft lbs and by 5250 I'm down to 375.

High - New setup shines

           On new dyno I peak HP at around 5200 RPM (381 HP) and at 6200 (my current shift) I am still in the same area

         - On old dyno I peak HP at around 5200 RPM (374 HP) and at 6100 RPM I had dropped to 340 HP)

 

Now I'm planning to hit the track on Wed to see which set of numbers are closer to the truth.  Either way, the power curves are a useful tool and I'm happy with how my car is performing right now.  

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Well....I got mine dyno'd this past weekend...

Torque down out of the hole(20 ft/lbs) and 30 hp down(from a dyno run ran when I had a ported 5.7L intake). What is really curious is the 30hp drop at exactly 4600 RPM, on graph it looks like a huge drop due to knock but we data logged and NO knock. 

I had a performance shop do the work for me. My tuner asked if it was hooked up in reverse(short runner first then switching to long runner)? I assumed and have read that the default setting is for the manifold to be in long runner mode?

I'm returning to the shop that did the work to diagnose if it is in fact wired in reverse, the tuner/technician says it would explain the graph and my disappointing results. NO ONE wants to modify, only to end up with less performance than they had.

Shows our "butt dyno's" are not reliable.

If it turns out that this is a dead end, I'll move on to the Edelbrock Gen 3 intake, it guarantees 30hp over stock. I really was pissed at "going backwards" on performance. If anyone else has dyno reults on this mod, I'd love to hear about it. If it's not hooked up in reverse, "The Eagle" is better off with a ported stock intake than trying to find performance in a 392 manifold.

Thought you'd like some real world data.

Regards,

Mark

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Make sure your MSD rpm switch is as follows: RPM "ON" set to 46, 48, ect (For 4600 rpms, 4800 rpms....)
RPM "Off" set to 80 for 8,000 rpms
Cylinger set at 1 for V8 with coil packs

Sounds like the MSD is setup backwards to me. You should gain around 25 lb-ft on the low end, see a slight dip when the short runner kicks in at 4600/4700 rpms, then the HP continues to rise a bit but not much. Definitely should not lose a lot of HP.

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I know this is an older thread. I have mine almost completed. Did you have to use a wideband bc the higher flow rate with the 6.4 mani?  I have a CAI, long tubes, catless, pypes pro race muffler and custom tune. 

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