small block chevy breaking up under load

I have a pro charged small block chevy that keeps breaking up under load and just noticed that the spark plugs are all black.

Welcome AF, too rich, fouled the plugs, too weak an ignition system to fire the higher cylinder pressures, wrong heat range plugs are some possibilities.

I would try leaning out your air/fuel mixture a little bit, either you are getting too much gas into the cylinders or the ignition system is malfunctioning and isn't creating a hot enough spark to ignite the fuel properly.

thank you ill try all of that but i am running a msd 6al boost box and high output coil with a msd billet distributor. think i should lower the jets in my carb to.

Try hooking a spare spark plug (of the same kind that are in your engine) up to one of your spark plug wires and see what kind of spark its getting.