FYI on the issue, I am now using a clamshell firewire 466MHZ with 10.4.11.
First, I had the original HD of 9GB. I tried to install 10.4 with a DVD but the dvd drive was too slow I guess because it never worked. What I had to do is boot this mac from another computer and use CCC to copy the system from the other mac to this one. It worked but I had to tweak around to suppress the recurring messages from CCC telling me that I needed to sync with the original computer.
And yesterday, I went for the plunge. I totally dismantled the clamshell, removed the HD and replaced it with an 80 GB used HD. And that newish HD has again 10.4.11 and it is working so far. It is much quieter than before because there is no humming from the HD.
Hoping you'll be as successful as I was in my swapping.
Emmanuel