Help with headers

I have a 2003 ford mustang gt I've put a 1965 ford mustang 289 vs engine in it but I need headers that fit having problem cant afford alot right now but need to get car done when I put in yr of car and yr and type motor it gives me nothing g can someone help me to find what I need
 
Wow, talk about going in reverse......
You have a unicorn, I bet nobody has ever done this swap before so I give you a couple options, look for engine swap headers for your year body with a push rod 5.0, I doubt there are any, so likely will have to custom build them, good luck.
If you're into fabrication you could possibly build them yourself.