ok, PR'ed in training, now what?

First, congrats on a speedy 100.  That's awesome.

There definately is a correlation between faster 100's and a faster longer swim.  To go from a 2:05 to a 1:36 requires a huge improvement in form and efficiency in the water.  This translate to any distance.

There's probably an extremely strong correlation between 100m times and distance times until you get to the 1:00 area, at which point strength and fast-twitch muscles start mattering more and (at least among competitive swimmers) you start getting specialization into distances.  It still takes technique to improve faster than 1:00, but it's mostly not the kind of technique that'll improve your distance pace as well.

However strong that correlation is, it's probably not as strong as the correlation between your distance pace in training and your distance pace in a race.  So I'd aim to measure a long swim if you're curious what your race pace will be like.

thanks I will try that...I did swim in HS for a year competitively many years ago so I guess I was able to improve a little faster than average once I got refocussed on what I was supposed to be doing...thanks again

Now what???

Shoot for a 1:25 100y, and hold 1:40 for 1000y.

I was at a similar point you were at starting at 2:00+ minute 100's.  I remember getting down to sub 1:40 for 100.  I swam a little more, worked on some major flaws I still had, and it wasn't much longer before I was swimming 1:22 for 100 and 1:38 pace for 1000.  Since then though...improvements have taken much more work to get even 1-2 seconds.

ETA:  My biggest problem now is translating my pool times to OW.  There's a big difference for me.

I am just a smidge slower than you - 1:40 is a recent PB for me.

One thing I have found true with previous breakthroughs is how it is possible to back off just slightly on the intensity - say 10% of perceived exertion - and have two things happen: 1) swim much further than the PB distance, and 2) be surprised that it really is not THAT much slower - fairly close to the PB pace.

Lately the coach in our tri group has been having us stretch our pace for longer distances by stringing together several swims with a very short recovery - say, swim 100m close to your PB pace, and repeat it 5 times with 10 seconds recovery between. One we did recently was 200m/150m/100m/50m, again near best pace, again with just a few moments' recovery in between. The last time we did this, I had renewed (hopefully justified) confidence that soon I would be able to swim continuously at that pace.

First of all, congratulations on your swim improvements and keep up the good work.  The faster you can do sets of 100's, the faster you will be able to complete your OWS.  Right now I can do a set of 10 x 100 on a 1:30 or 1:35 interval in a SCY pool (coming in at 1:22-1:25).  This translates to an OWS pace of somewhere between 1:35 and 1:45 per 100.  If I want my OWS swim times to be 1:25 to 1:35 I will need my 100's to be in the 1:15 to 1:20 range meaning my intervals need to drop to 1:20 to 1:25 or so.

Keep working on your stroke, improve that swim to where your 100 intervals are lower.  This will result in better OWS times for sure.