I do not know enough to answer this question. The specification says to use 2.85V. I imagine that you could get some ringing on the high signals because 3.3V is a little too high and your highs will be a little underdamped, and your lows will be a little overdamped. With slow original SCSI and for these applications, will it ever make a difference, or will it be "good enough"? I just don't know. There was probably a time when I could have calculated/analyzed it, but those days were about a decade ago....
If you can get 2.85V or an adjustable Vreg without blowing the budget, I'd go that route. I think the LM317 is adjustable, but then you need more components. You might hunt around at National Semiconductors, TI, and Linear Tech (I think someone bought NS a year or two ago) in their power and control or voltage regulation sections and identify a few simple chips that can do the job, then hunt them on Ebay to see the pricing. Also, take a look at questcomp.com. Sometimes they have stuff in stock at lower prices than Ebay. The LT1086 is a good choice, if available in a smaller package than I've seen it in, but I don't know about pricing. LT might have something similar with a lower current rating. Oh, it's worth checking Digikey and Mouser as well. Oh, you're in the UK right? So Farnell?