WOW T-Bird that pic is awesome clean and clear...
V8 in UK,
I doubt the timing light was bad because they don't usually advance. You could have a faulty module that is over advancing, if your dizzy is locked your springs are not losing control.
I guess I would change the module out, if that does not fix it get another dizzy and try it.
50* of timing will kill just about any SBC making decent power as it will burn pistons and kill ring lands.