[flyin ryan]

The project will drain all your assets and break you to the point where you'll be a sloppy homeless guy sucking dicks on the street corners for meth and eating half eaten big macs from various trash cans all because you wanted to stuff a 5L into a 99 v6 car

Seriously though sell the 6 banger and pickup the 8 and be done with it.. convertables are on the cheaper side of things because they are less desired for speed and higher on insurance so weigh that verses becoming an electrician over night(redoing all the wiring) and dicking around with whether or not a sn95 5L k possibly fits without major clearance issues makes more sense. Unless of course you have the funding to over pay some douche to totally rewire your car with electrical tap and butt connectors for you because there is no plug n play harness that I know of that's remotely close to being exactly that, plug n play.

I helped swap a 03 power train into a 01 and it was a big pita.. every time we turned around there was some bs wiring that had to be totally removed and redone/reran it was a nightmare but once the car was done it ran like a mofo. I personally wouldn't do again myself, If I had to have it i'd save up to pay some one else to do it while keeping a close eye on how well there work is

in any case good luck

[99FiveOh]

I know this is old but I wanted to chime in since I've done the exact swap the OP was asking about.

If you have a donor car handy the swap is really straight forward. The actual chassis stampings are the exact same from 94-04 so every little wiring harness, nut and bolt will transfer from the 94/95 5.0 to the 99-04 body. But EVERYTHING has to be transferred over! You have to swap over all the wiring harnesses front to back, complete fuel system including tank and lines from engine bay to tank, K member from 94/95 V6 or 5.0. I used the 99's dash cover over top of the 94's dash frame/wiring so it wasn't bad at all.

The entire project took me about 2 weeks to complete in my back yard and mostly in the grass and I was more than pleased with the result. I really enjoy watching peoples' heads snap back to my motor as they start to dismiss it as your every day 99-04 GT. I have a 5.0 emblem on the back with the V6 bumper still in place and it's a great conversation starter. I got people at street lights asking "does it REALLY have a 5.0 in it? lol

Anyway, unless you have a complete donor car sitting and waiting, I wouldn't recommend doing it. But 94/95's with beat up exteriors/interiors are a dime a dozen and are usually pretty cheap around 1000-2000$.

Here's a link to the build with lots of pics, step by step documentation and discussions:
Project: Swapping 94 Gt drivetrain to 1999 V6 Vert chassis | Mustang Forums at StangNet