Why won’t my truck start

Why won’t my truck start My 06 fl50 is a v8 supercharged but the motor locked and my stepdad got a v6 installed in it. I wanna say prolly a few weeks I into having it my dad put some speakers n a radio in it and it caused my dash to go out . Last night my truck was running hot and we noticed it when it started to like stall on going .