I can get a good deal on a set of aftermarket shorty headers off of a 5.0 mustang(barely used). But, will they fit? If they don't, what do I have to do to make 'em fit?

They drop right in if they're unequal length shorties.

What knid are they? Any idea?

I'm not sure what they are, my friend knows the kid who's selling them and he knew I was looking for parts so he told me. I told him to get me more details...

If they're MAC headers, they're gonna be a bitch to install - especially used. Once they're heated up and cooled down and whatnot then taken off, they're known to slightly warp due to the individual flanges on each primary. I had that problem when I went to install mine in my driveway with normal tools and it was a bitch, to say the least.

Just buy them new. I think it will save you time. I have Mac or maybe something else. Took me three hours and it was good to go!

Will equal length shorty headers fit?