The document provided states maximum "permanent" output at 155hp, I assume this would be another way of saying max continuous power.
From what I've read online the 135hp fitted to the Warriors reportedly "feels" like it's 135hp relative to the normal O-320 160hp. The basic weight is increased on the aircraft considerably and cruise performance down around 10%.
With an engine life of 1200 hours it would cost more including offsets of fuel costs to operate than the Avgas engine. It all depends on what happens at 1200 hours as well, overhaul, re-manufacture or replace? With the new O-360 you would get a couple of useful cheap overhauls out of it or a reduced price factory exchange.