eating flywheels help please
 

iam having problems with my sbf 8.2 deck 363 eating flywheels and sounding like a chevy that needs to be shimmed diddnt start till i locked it out.I was having some tuning issues so i locked it out and it helped but i didnt have a start retard...33deg of timing it kicked back a couple of times while hot broke the flywheel. so i bought a digital retard from msd. and put the start retard at 20 deg..same problem it kicked back broke the fly wheel i think again.disconnect the coil to take the fire away and it sounds the same. sooo is 20 deg too much and it tried to light the wrong cyl.kicked back and broke again.or do i even need to worry about locking it out with a 200 shot? sorry iam rambling but i want this fixed.it is a 4.125 bore with 13.5 compression.
stock 157 tooth bell ford mini starter c4 trans