Anyone ever run Speedmaster Heads on their small blocks

Anyone have any flow specs of the 915's? It would be fun to compare.
Bigger/ better than a stock J head.

Stock J head: ................. Speedmaster as cast:
.100 62/47 .................... 64/49
.200 112/99 ..................... 120/97
.300 157/128 .................... 176/134
.400 193/137 ..................... 221/153
.500 200/140 .................... 240/164
.600 201/141 .................... 250/168