Originally Posted by A.Winthrop

Hi WakeRider,
.
Your serial numbers do not lend support to your theory that
your bike is a Centurion. Neither does your groupset as
listed but components get changed so there is no way of
knowing for sure.
.
Your Shimano 600 SIS derailleurs would, if original,
suggest a 1986 or later model as '86 was the year indexed
shifting (6-speed) was introduced to the 600 group. But a
Centurion Ironman Master, the model of '86 through '89
that would have sported those derailleurs, would have also
sported most of the rest of the 600 groupset (cranks, brakes,
et al). And your rims would have been 700c, not 27x1.
.
So my guess is that your frame\bike is not a Centurion at
all. BF's T-Mar, the creator of this thread, might be able
to descern something from your serial number and maybe someone
here will spot something unique and telling from pics of your
frame when you post them so maybe you'll find out what it is
eventually.
.
Good luck.