Higher idle

[gt6493c@prism.gatech.edu (gt6493c FLUHR,ERIC J)]

Speaking of unusual idling, I wonder if my engine has a problem.
A few months back I had to replace the hydraulic lifters and fuel
injectors on my '85 GT.  Before that, the car started unbelievably
quickly, usually on 1 crank of the starter motor.  Highway mileage,
which is supposed to be 25mpg, came out to around 23mpg.
But I didn't pass FL emissions, and the mechanic that inspected it
said I needed new lifters and injectors.  Well, the lifters I knew
were bad but the injectors I thought were pretty good.  Anyway
I replaced both, and then had the guy set the timing and adjust
the CO.  After all this was done, I noticed the car now needs several
cranks of the starter to start up.  Not excessive by any means, but
still a far cry from the 1 crank --> start days.  Also, the idle
was high, about 1000rpms.  So we set the idle (my Dad was helping
me), or at least tried to.  We adjusted the small screw in the intake
manifold, which he (my Dad) said was the idle adjustment.  Well, we
lowered it as low as it could go, but could not get the car to idle
<900rpm (right now it idles at 900).
So is there a problem or is it no big deal?  I haven't noticed any
difference in how the car runs.  I thought maybe it was burning
the fuel more efficiently, maybe the new injectors were needed, but
my fuel mileage has not increased any.  If anything, it has dropped
a bit.  
As far as I can see it is not big deal, but I was just curious as
to a reason.
Thanks,
Eric