^ I don't think more cam would help you. Have you tested turbine drive pressure? I think with a single that size you would find it's getting up there and that's what's making it peak early.
You could keep your current cam and go to twins, reduce turbine drive pressure at the same boost level and pick up a ton of power and 1000 usable rpm.
More cubes would make less power with your current setup. (again because of drive pressure to boost)
Its basically a 76mm Compressor, but with an 88mm (or 96mm inducer depending on how you want to measure.) Turbine setup with a T6 flange and a 1.32 A/R. Very unlikely a 360" motor at 6,000 RPM is even close to choking on that.
There are guys pairing the billet 80mm wheels with this turbine making over 1200hp on LS motors, so I don't think I'm really at the turbine limit.
What COULD be possible, is that the single 1 7/8" manifold outlet is the choke point. Hard to say without trying other stuff. But as you mentioned, that is a lot of work to build a set of headers just to "what if".
I have no interest in pushing this combo any further. It's plenty fast for a street car with only a roll bar, and is reliable enough to bracket race.
