CARB compliant GENIII LS exhaust manifold (1 Viewer)

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Jan 28, 2004
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In the early stages of part picking for a 6.0 LQ-4 swap into my 80. Anyone find a stock exhaust manifold that fits between the frame rails? Frame rails measure 25" between the rails. Truck manifolds are way wide at 29.5" or so. Late model corvette manifolds are 27.5" or so wide.

Can't have air injection port on the manifold as my 6.0 has no air injection.

Suggestions?
 
Joined
Oct 22, 2010
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Parker, CO
I planned on using LS3 manifolds but they would have required some frame notching. I used the hooker street rod headers. Oddly, I had no issue with emissions. Air Care Colorado is just as strict as CARB and the refs didn't have a problem with headers. They wanted to see that there were two cats and 4 O2s in place and active just like stock. Plus all of the EVAP parts have to be in place and functional. That gets you past the visual. Then they plug in the scanner and confirm all of the readiness monitors are in ready status and then you are good to go for the dyno test.

Not having air injection or EGR makes it easy.
 
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If there's no carb eo # don't waste your breath. The stock corvette manifolds should work and can be had on the vette forums cheap.
 
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2006 corvette. At least that's the model year I sourced my ls3 manifolds. But they wont work unless you plan on notching the frame. You might also want to check out the ls3 camaro manifolds. They are used frequently when swapping LSx motors into jeeps and they are rear dump past the 4th cylinder and pretty tight tuck.
 
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Are you able to squeeze the outlet flanges of either between the frame rails? The late model vette manifolds I picked up have the flange alignment in the wrong direction (they flange aligns side to side as opposed to a front/back orientation).

Any chance you have manifold part numbers?
 
Joined
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Denver, CO
What about having a set of stock manifolds altered to fit? Either have the flanges rotated, and/or have the dump repositioned slightly to allow clearance?

Also, I would still contact the certification folks as they may allow a simple header knowing that it's only a physical modification from stock and not related to any emissions equipment??
 
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if only the Great State of California were so reasonable! Although many of the referees are cool and "get it", I suspect they want to cover their asses. Can't say I blame them. Now modding a stock manifold might work but I really don't know anyone with the talent to weld a cast manifold back together.
 

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