[CentOS] grub issues on reinstall.

Hi all.

sorry for an immediate question after subscribing, but I've managed to
back myself into a frustrating corner.
I've done some googling and come up dry, I figured I should try to
post to the list while I dig through the archives.

I have an issue with grub on a centos reinstall.   my system
previously had 1x 120g ide drive, 3 1tb sata drives in raid 5 md, 2
300 g in a raid 1 md,the /boot partition was on the ide drive, os on
the raid 1 in a volume group and everything seemed fine.    I
downloaded the x86_86 iso a few days back and decided to just to a
complete reinstall rather than burn myself with some odd upgrade path
trying to put newer, larger drives into a md with a much smaller
drive.

I've since purchased some new drives and changed to 1 120 ide, 4 1 tb
sata, 2  3tb sata.    I've tried a few different combinations of
install locations (e.g reused the ide as /boot, a 512 mb slice from a
1tb drive for /boot) but every layout I try seems to end up with a
grub config that can not find the OS (if memory serves, the message
comes back as error 15: file not found, hit return to reboot)

the thing that seems odd to me is when I do the reinstall, the hdds
seem to start much higher than I'd expect.   there's no /dev/sda, b,
c, d, ... I think they start at i.

does anyone have some suggestions for what to try for this issue?
Thanks.

-- 
Even the Magic 8 ball has an opinion on email clients: Outlook not so good.