Installed lower cowl to check alt air door arm and needed more trimming. Prob should have tried harder to place it on the vertical, but committed to bottom of FAB for now. Match drilled the last camlock hole that needed repair on bottom of lower cowl. Installed the floating receptacle and fits well now. Spent a lot of time trying to figure the engine baffles and modifications needed for Bill Lane plenum. Installed the aft baffles for number 3 and 4 cylinders after digging thru several hardware bags in firewall forward kit.