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Down pipe questions

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Old Apr 2, 2011 | 06:12 PM
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Dom87SS's Avatar
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Default Down pipe questions

Anyone know the difference between the down pipe flange of a 3.8 manifold and the ls4? I'm looking at bolt pattern (location and size), flange angle, location relative to chassis, and shape if it available.
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Old Apr 3, 2011 | 10:26 AM
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well i did some searching around for install pics and stuff of down pipes on LS4 and L67 motors and they are not a ton different. it looks like the flange area is relatively the same with 2 bolts and the same over all design of the flange. not the angle may be slightly different and it seems like the LS4 manifold may protrude toward the rear a little more than the L67 does. but the angle of it seems very close between the two.

some may be wondering why i am asking this, and its because i have a 3" catless ZZP DP on my GTP which is going bye bye and if i can id like to salvage it and possibly reuse it on the GXP when the warranty expires. And after lookin at it, it seems like it may just work and it will be a lot cheaper to do this mod to the car when most of the parts are already paid for and here. Im gonna look into a little more, but it may be one of those things that if you run across a nice DP for a 3.8 for cheap it could be adapted to you LS4 for relatively cheap and from what im reading pick up a noticeable gain from it.
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Old Apr 3, 2011 | 03:30 PM
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hard to say i havent seen the underside of a GTP in a long time now. anything is possible with a welder
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