Anyone have desktop dyno be willing to get me a ballpark?

Yes it's inaccurate.. Straight away I can see a carb size of 600cfm @ 3.0Hg. 4bbl carbs are rated at 1.5 Hg. So if you trying to use a 600Cfm 2bbl, then your putting a "choke" on the engine.
8.5 :1 comp?? Really, my Briggs & Stratton lawn mower has more comp than that :)
What size is the "small tube header" 1 1/2 ?? 1 5/8 ?? 1 3/4 ?? What sort is the muffler? Free flow? Smog type ? with lots of back pressure. That program take a lot of inputs for granted.
I found EA pro was closer to the mark because it has a far better range of inputs.
That program always overestimates power readings, every half decent engine builder will tell you the same. But as they say, you get what you pay for.