If you install that new drive into your SE/30, you shouldn't have to do anything further. Now, what could happen is it will either boot into System 7.5.5, like you mentioned, or it will give you a blinking question mark inside a floppy icon. If that happens, then the Mac is having a hard time trying to find a System folder to boot from. This is where you'll need to have your Disk Tools floppy handy, so you can run some utilities to check for disk problems.

A blinking question mark can happen for two reasons: 1.) The drive was wiped by a previous owner, or 2.) The System Folder or files are corrupted and need you to boot from a Disk Tools floppy to get back in working order. If the drive was wiped, you'll need to repartition and reformat the drive before installing the System software. Use HD SC Disk Setup version 7.3.5 or Drive Setup to get that hard drive ready for installing the System software.

But first, let's just assume that the drive is good and has System 7.5.5 already installed. After it is hooked up and you turn on your SE/30, if it boots into the System software, you're all set. No further work needs to be done. But be prepared just in case the above happens. I'll be here to help you out likewise.

Give it a try and report back with your results.

73s de Phreakout. :rambo: