Long tube headers on my 72 duster 318

For a budget of $250, you won't be getting much more than the standard headers that trap the center link and hang a little below the K member.

That said, I've been running either Summit or Jeg's (can't remember which) cheapie headers for the last several years with no problems, after massaging them to fit, other than scraping them once or twice.

I think they go for around $100 and you'll need to invest in a ball peen hammer to get them to clear some of the tighter spots. Give yourself plenty of time to get them put in, like a whole day.