I reckon Jabba might just be right. My old IO-520 had the Continental injector nozzles designed continental engineers to all have the same size orifices.Spare parts loved it--only 1 part number for all 520 nozzles. If I leaned much past peak EGT the engine ran rough. Then I got GAMI nozzles. They vary the nozzle sizes to give as near as possible equal mixtures to all cylinders. Now I can lean way past peak EGT and it"s smooth all the way. Of course the further away from peak I go the less power is produced but it is smooooooth. I can actually use the mixture control like a throttle . Push him in--more fuel = more power . Pull him out ---less fuel = less power. But what would George Braly know-- he only designed and tested these things an now rumour has it he's invented an unleaded replacement for 100 LL. I wish he would leave engine and fuel design to the experts.