Hi all I have a 1984 polo 1.0 amd kust got a later mk2 1.3 carb engine I have got a loom that works but do I need to swap the interior loom aswell or not

If your 84 is an early engine (points ignition, rocker cover bolted on around the outside, not 3 bolts down the middle), then engine bay loom yes, the rest, no.

So just swap looms over and it will work. The loom I jave with it is out of a 2f and its still using the ecu for spark would that loom just plug in by the fuse box