I would have thought it was an Alpha
box, but unless the sun was in my eyes, it says "VAX 4000" on one
name plate on one end, and "Model 710" on a name plate on the other
end.
I think the sun was in your eyes (or someone has
been playing with labels). It might be a VAX 4000-700A
or a VAX 4000-705A or it might indeed be an Alpha:
a DEC 4000-710 (this was the Fang, a follow on to
the DEC 4000-610, the Cobra). You can add a
second CPU to obtain a 4000-720 (similarly you can
get a 4000-620).
It's still in the back of my station wagon, so I
haven't even
fired it up. From the stickers on the devices, it's running UNIX
(/dev/whatever on all the disks and tape drives).
It's almost certainly a DEC 4000-710 (which is
probably a win: they are rarer than VAX 4000-70x
machines IMHO). I don't think Ultrix ever ran
on the VAX 4000 machines.
I bought it without powering it on because a) I wanted
the TSZ07 and
it was cheaper than the shipping alone, and b) they don't have
a 20A plug at the surplus barn (the one with the blades like (- |)
not the usual (| |) for a 15A plug).
Sounds to me like you won big time here :-)
Antonio