Need Misfiring help
 

Mazda sports racer with an early 12A bridgeport, engine will run fine part throttle but falls flat on its face no power under full throttle load. 48 IDA with 205 mains and 180AC, runs one msd fire lead and trailing at same. Went through the carb and up and down on jetting all weekend with no change, I think its ignition getting weak under throttle load. We use two hall effect sensors in the distr, triggers one msd which fires both coils. this is a common setup and works well for others, msd plug wires ohmed out. I am at a loss need all suggestions