"Prop was an APC 14x7 and the fuel was 30% nitro and 20% oil. The DZ 70 turned 10,420 and once warm turned 10,290. The FZ80 turned 10,530 and once warmed up it turned 10,410. Both of these were on a header as I didn't have time to install the mufflers. I don't run the mufflers so not sure how much the drop the RPM if any at all."

This is interesting information BUT I would point out that Yamada San has emailed me that the FZ80 achieves it's HP peak near 15,000 rpm. This is how to interpret the "practical" rpm range. So the 10,000 range is way down from the HP peak. On the other hand, the DZ is not supposed to be run any faster. Whenever you test and compare engines you can choose optimal conditions for one and hobble the others.

With a 14x8 prop and 10% a Saito 82 and FZ 80 may be close. On a 11x7 prop and 30%, NOT CLOSE. I have not tried this.

NOTE: There is an obscure line in the FZ80 CDI instructions just for me !