In back to backs that I have witnessed....AND....the graphs I've seen, bigger primaries always produced more or roughly equal torque below 4000 RPMs and more torque above 4000 RPMs.

HP was higher and consistent....meaning 5-8 HP through the entire curve to as much as 15 to 18 HP through the entire curve. But basically, the HP curves would usually look the same.....just moved up on the graphs.

My sample group is relatively small.....maybe 10 or 11 total....but they've been consistent.

KW