Who's doing your props? Wilmington? I see you are in Long Beach, we are in Alamitos. Both turbos are brand new. We've run with the breathers off too. Right before COVID, we cracked the exhaust elbow on the stbd motor, which started the whole process. Sucked soot into both motors 1/2 btwn our port and Catalina on the return. Aftercoolers, blowers, turbos, injectors all rebuilt or replaced. Everything checks out fine w/out load, it's when you put a load on - we start to smoke. We played with the injector timing which did help a bit, but put it back to stock timing of 1508 vs 1484...made it worse. We can't reach 2350 loaded, so that's why I am thinking, over propped! Puffing black smoke and not making full RPM is kind of a sign we need some pitch removed - I know black smoke indicates lack of fuel or air, but could also mean the wheels.....just so frustrating!