Depends on what kind of runner you are. Just like extrapolating 5k times from a 1500 PR, 10000 potential from a 5000 PR, marathon ability from a half, etc, one performance alone isn't that instructive.
That said, 1000 and 800 are of course proportionately closer than those others. I'll give you a 2:04, assuming you're more of a 1500-800 guy and (i.e. your strength is good and your 1000 is pretty much par for your 800). If you're more of a 400-800 guy who falls off hard at the 1000, maybe 2:00-2:02? Faster? Again, hell if I can tell you from just one time :)
To paraphrase my pal Ventolin, give us something more so we can draw a line here.
Finally, how is it that you have a reliable 1000 PR but not an 800? How often is the 1000 actually run where you are?
well I can't run the 800 for whole 3 weeks,so I'm just interested,btw. I'm a 400m-55 seconds guy, with last year PB on 800m 2:05.08, I'm an ex hurdler-multievent,first race of the outdoor season was 1000,and not the 800,that's it,is this better?:)
well I think I'm a little faster then those times now,but who would now,till the race :)
if it helps I ran today workout 3x4x200m , 1 min rest between 200's,and 5min between sets
3.set-29.8,30.1,30.4,30.5 (it was windy last set)
your opinion now?:)