80-pin SCSI drives (the connector on these is called an SCA connector) are typically used for hot-swap enclosures, because power, jumpers, and all data signals are inside the 80-pin connector.
You can buy some UW->SCA adapters that plug into the 80-pin connector and break it out into a 68-pin ultra-wide SCSI connector, a set of jumper pins, and a molex power connector. See this example from CDW.
Once you have these, then a standard LVD SCSI controller card will work.
You're talking about a 80pin SCA connector. It's a single trapezoidal shaped connector that has both signal and power in it right?
There are adapters. I don't know if they handle U320 but I'm sure there are some that handle U160. They have an SCA connector on one side of the board and a 68 pin and power connector on the other side. I seem to remember they generally cost about 10-20 bucks but you might find a deal on ebay.
Then go and find a controller- if you're not using RAID and just have a single drive or maybe two, best bet is a Adaptec 29160. It's only U160 but it's cheap. 29320 is still kinda pricey I think. Or you could go with one of the many offbrand U160 controllers.
EDIT: nevermind, looks like 29320s are like $50-70 and 29160s are $10-30. Still pretty cheap but with a single drive, you'll never even reach the limits of U160. I'd say go for the cheaper card.
Or toss the drive and get a bigger IDE/SATA drive that has essentially the same performance and is most likely less noisy.