No fire in my firebird

I have a 1994 Firebird that will not fire. The brain box had to be replaced shortly after purchase and cranked fine but a so called mechanic who was a friend claimed to be improving its performance and it has not cranked since. There is no fire at all. Can you please help?

need more info what engine and is it not cranking or not sparking

It is a Formula V8 and it is not sparking. Beautiful car by the way

well i gues the question is what did yer friend do to it
then go back to basics ,fuses ect im not real familier with the lt1s imsure john will be real helpfull if he sees this thread
o thank for the compliment on my car

thanks