1989 5.0L swap compatibility

Wiring doesn't matter if you are tearing the engine down to a short or long block and just swapping your entire top end. If you do that, you can get the long/short block from from any 87-95 Mustang 5.0 or 87-92 Lincoln Mark 7. Strip it down to short/long block, and just swap all your engine components over.

If you are looking for a 100% direct swap of the entire engine, youll need to find an 87-93 Mustang 5.0. You can still use the Mark 7 engine if you do a partial teardown and reuse your accessories

If you want a little bit of an upgrade, you can get an 96-01 Explorer/mountaineer motor. They come with GT40/GT40P heads, and a slightly different version of the 93 cobra intake. Strip it down to the long block, swap in your HO cam and use that as the foundation. Just need to be mindful of exhaust clearances of the GT40P head spark plugs.

Or strip it down to a short block, swap on all your top end parts/cam and sell off the GT40/GT40P heads and intake for $100-200ish. Explorer 302's tend to be the only 302 found in a junkyard these days. If you can find a foxbody or Mark7 with the engine still in it, it's a rare sight.

I guess the question is what portion of the engine do you intend to swap in? Short block, long block, or complete?