Still explaining the gap in the runs wrong. The runs with LOW gaps make more nuts, not other way around.
I dont think there is a difference in possible Nut-Str8s in both combinations:
8764 can make NutStr8: 235, 345, 356, 357, 456, 457, 458, 569, 579, 589, 69T so 11 NutStr8s
8764 can make Non-NutStr8: 567, 568, 578, 79T, 89T, 9TJ so 6 Non-NutStr8s
8654 can make NutStr8: A23, 234, 235, 236, 347, 357, 367, 457, 467, 478, 579 so 11 NutStr8s
8654 can make Non-NutStr8: 567, 578, 678, 679, 789, 79T so 6 Non-NutStr8s
The difference is in the possibile scenarios where You can make big NutDRAWS or made hands with redraws!!!
8764 can make a 17-card-Str8draw with 11 Nutouts on a 56x Flop or a 16-card-Nutdraw on a 953 flop. There are more flops You can hit pretty hard with Str8 + redraws (like 235 or 356), Str8draw plus 2 Pair (like 456) or similar.
8654 can only flop 237 for a 13-card-Nutdraw or maybe 743 for a Str8 plus Redraws. But there are less possibilities to hit the flop big than with 8764.