Just be a mechanic if he can’t pull off a 5.0 “swap” into a 5.0 mustang.It is also possible that you are using the term "mechanic" loosely.
Kurt
Need a little more info. And maybe a pic of the engine compartment could help.
Is the engine cranking over and not starting or does it not crank good?
We definitely need a lot more info. Can you provide good close-up photos of the engine in various areas so we can see what's done and not done?
ok doing that now but can something like this stop the car from starting?
Fix the fuel leak first. It’s a fire risk of you start the car with fuel spraying around.
Does the engine physically turn over?