Here is something to consider-

The gear ratio of a Raptor 30 is 9.56

A OS 32 peak HP is 1.15 @ 17,000 RPM
Practical RPM range is 2,0000-21,000

Running a head speed at 2,000 RPM would have the OS32 running 19,120 (well over the peak HP range)

Verse

Running 17,500 would have the engine running 16,730 which is much closer to the 17,000 peak HP 17,000 peak HP

The reason we chose a head speed has allot to do with peak HP, to get the most torque and power out of the engine.