I think I ran the same test as Ed.
The Fox Deluxe I had was the early first production run one ( double taper cylinder bore).
The OS FSR 32-H came out of a Hirobo Shuttle heli.
I ran these tests on a test bench on the same day.
I ran then open faced because the OS heli muffler couldn't in the engine stand.
I used 15% nitro and synthetic fuel.
I was at 6K feet altitude in Denver.
What I wanted was a sport engine that would out run the COMO 40 PDP. I needed the Como for our Quickie 500 races.
I wanted an engine that would turn a 9x6 rev up prop at over 16K rpm.
The OSFSR was the ringed engine and had the large heat sink head
The Fox had a true chrome ABC P&L and that cast spinner that came with the early Deluxe engine.
I will say that the Fox Deluxe out ran the stock OS in the 16k rpm band. It wasn't even a contest.
Some notes; the carb on the OS was rich in the mid rand with airplane props. (remember that heli engines are set up to run at close to one rpm [around 15k -16k rpm] no mater the load [collective, pitch])
This test was done at high altitude where the low compression ratio of the OS is at a disadvantage.
The stock OS 32 -h started to run well in the Shuttle after I started to use 25% plus nitro and a Magic Muffle pipe. (at hi altitude it need this to get descent cylinder pressure and not over heat)
Sorry I don't have any note from that day. I doubt I even took any as this was for a my sport ship a Great Planes, Super Sportster 40.
The SS 40 flew great with the Deluxe 40 on a rev up 9x7 for many years.
I did use an OS FSR 32 ABN in an Andrew's minMaster (a 20 size ship that didn't look like a Hershey bar on top of a cigar box).
I thought the OS FSR 32 ABN was a great little engine. I had to use a K&B 4011 on pipe on my Midwest Little Stick to equal the performance of the miniMaster
Now the next OS 32 ( I think it was the OS 32SX-h) could run close to the Fox deluxe (I never ran the OS 32SX side by side).
As for the best power to weight in the 5cc to 6cc class engine I found that the early Webra 28 and 32 (true ABC) could out run engines in the 16k to 17k power band. what I didn't like about them was the hose clamping on of the pipe. I often had problem sealing the header to the engine.
So the short of it the Fox Deluxe was more powerful than the OS 32. This isn't too surprising as the little OS gave away 1.5cc in displacement and had a head that was to large in volume for rational levels of nitro.