Drew,
My focus, right from the start, on this build, was/is a MILD street build and not a high performance engine. This engine is limited to 5200 rpm and falls off, extremely fast above that but, NOT because of the carburation. It has EXCELLENT performance, to that point though!
The OP says this, regarding my suggestion about a smaller carb:
"Yes, thought about it, however the throttle response with the 750 and single plane streetmaster intake were nearly identical to the 650 and dual plane preformer that we decided to keep it instead."
That statement tells me that there was a noticeable difference but, decided to run the 750, in spite of it.
Now, that could have been because of the DP manifold, the smaller carb or just because the smaller carb is jetted better. I don't know but, no one else does either.
The 750 is running fat on the dyno and only clears up near the max HP so, by the dyno results, how can it be said for sure that a higher velocity, optimized A/F won't make more torque? But, some say that it's not possible, at least, that's the way it was presented to me as I'm told there is no reason to try it. Maybe that's true but, then explain to me why a higher velocity, possibly better atomized A/F mixture would produce less torque? Not to mention, that it might also produce, overall better MPG.
Now then, I appreciate Brent's expertise, skill and knowledge and I think he is one of the best builders anywhere but, I'm just as stubborn as he and if you tell me it's not so, you have to also tell me WHY, not just blow me off like, if I suggest something it's just wrong.