An ACard adapter with an IDE to SD converter doesn't cost much more and performs a lot better.
SCSI to IDE to sd is alot of conversions, better off with scsi to ide to cf, since a cf is a true ide interface. less latency since no conversion to serial nature of SD but your experience may differ.. I have used a few sd converters on 4000 ide with a bunch of different cards, they work but i notice they aren't as snappy as cf and some are problematic with bigger cards.