I have two 4373 Slick mags on my IO-360 on my Pitts and she just doesn't want to fire. I've set the e-gap, checked the internal resistance and cleaned the contacts before installing. It's a 0 smoh engine, new plugs with gap set, and both mags timed perfectly at 25° btdc. The problem I'm seeing is the sparks from the mags are weak looking or intermittent. Both mags were salvaged from aircraft damaged in a hangar collapse during a hurricane. I removed the p-leads to eliminate the ignition switch from the equation and the condition persists.