I am working on a new WWI de Havilland DH-4 biplane and plan to use a DLE55 engine, mainly because it will fit in the long narrow cowl area.

Any thoughts on whether it will turn a 26" diameter prop with a 6" pitch at a reasonable RPN, sat 6000-6500 RPM?

This plane will onoly so fast anyway, even with 3 DLE55 engines! I do not need airspeed, just thrust.