No, just no. Ultra160 drives are usually back compatible; many Ultra320 drives are not. You need to check the manufacturer's data sheet for that drive and confirm that it can be set to a backwards compatible mode, SE or Single Ended, IIRC. And you need the right adapter.
But then, a simple USE THE SEARCH would have shown both of you that this has been discussed here before at great length.
Or, you know, Google.
*facepalm*