Yeah, I'm definitely thinking "tubed" for all those SBC exhaust tests. I just found some data on the LS7 head that comes from the factory CNC'd:

"the exhaust ports flow is as follows:

Lift ___.100 _.200 _.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650 _.700
#1 Exh. 57.5 118.8 176.7 207.3 221.7 229.7 235.9 240.8 243.9 246.2 247.9
#2 Exh. 56.2 115.4 168.5 194.4 206.2 213.4 218.5 222.9 225.6 227.8 228.9

The #1 exhaust port was tested with a 1.875” dia. Pipe 2.5” long.
The #2 exhaust port was tested with out a test pipe."

The CNC'd LS7 head's intake busts out some pretty stout #s too (360-ish), but it's a 12* valve angle and "next generation" compared to the LS3 stuff I mentioned above.