ZDZ 80 single with a Bisson w/a pitts muffler modified with 1" exhaust pipes.
Amsoil Dominator mixed as directed at 50-1.
TNC tach, 2000' density altitude.
I don't believe that the engine is fully broken-in yet.
The RPMs with the stock 7/8" exhaust pipes were 200 rpm lower.

24x10 Bambula sq tip 6100 rpm
24x10 Bambula swept tip 6400 rpm
26x10 Menz ultra 6200 rpm
26x10 Menz std 5800 rpm

Good Luck
John