I have a 1995 Miata with an LS1 in a V8Roadster setup and dinged Sanderson headers for steering shaft clearance. I am trying to make it CA smog legal with a OEM exhaust manifold or CA legal header and catalytic converters. Has anyone tried the OEM Pontiac G8 or LS3 manifolds with cats without moving the steering shaft? I am considering adding joints and an offset steering shaft if required.

 

I don't know if anyone has tried it, but can see your point. Food for thought....take a look at the 2009-2015 CTS-V setups. It is the same style but the cat is much smaller. I may even have a set laying around.

 

You might look over the CARB legal LS build that is around here somewhere.
As best I remember he utilized 2006 GTO exhaust manifolds and cats but I have slept several times since reading the thread.
Also going off memory, the fitment issue was not the steering shaft but rather the firewall.

I do know that the V8 Roadster subframe is different from the Monster subframe but I do remember reading several places where the Pontiac G8 manifolds will work with the Monster subframe.
Taylor Ray uploaded a series of YouTube videos where he did an LS build in his Miata and originally used G8 manifolds.
He has since switched them out in a search for more performance.
From looking at his engine placement compared to my car, it looks to me like the Monster subframe places the engine about 1"-2" further away from the firewall than the V8 Roadster subframe.

 

Thanks for the info. FlyinMiata uses V8roadster subframes and gets the EROD LS3 to fit but I haven't heard them address the steering shaft.

 

Why would they? The V8 roadsters subframe gives the new Sanderson headers sufficient clearance so you do not have to dent the crap out of them.

 

Didn't know that, what are those headers called?

 

Sanderson V8RLS1 Header Set, GM LS Engines (V8 Roadster LS Header Set) you specify which engine you have (LS1, LS2, LS3)