The Amiga's internal IDE port is not buffered, so you may encounter problems when using longer cables.
If the terminals are normal IDC types:
Rich

you can just detach them (be careful, as the clips are easy to break) and, with a bit of force, re-position them further along the cable. Then just snip off the extra IDE cable length using scissors (being careful to make sure there are no protruding wires which may short).
Regards