Is this possible at all ? the only difference i know of is the shape of the relays ? they are rounded instead of square.

Basically i bought a replacement engine wiring harness for my car a few years ago and when it got here i noticed straight away it was from an 88 or later car because of the relays and ive still not done anything with it.

Now ive bought a 5.7 TPI engine to swap my 5.0 for. I am getting the wiring harness with it but it looks a bit tatty, this harness i have sitting in a box though looks mint, no cut wires or anything.