I just finished the fabrication and install of a lycoming style crossover exhaust on my c-90 powered cub. Cly#4 goes to cyl#3-cyl#1 goes to.cyl#2. I replaced the 2-into-1 style exhaust, and can say that I'm fairly impressed with the results. About 30 rpm static and around 50rpm at 60 mph indicated. Has anyone else ever tried this?