Speed up a 2158-240? reference manual?

Does anyone have complete information about speeding up an Aptiva
2158-240? It's running at 350mHz. According to one source
(http://www.highdots.net/ibm-aptiva/upgrade-27008.html) (Upgrade), a faster chip
can be inserted. There's a broken link to a IBM's site with the
details... Any ideas where I could look for that now?

I've also seen claims that the current hardware could be over-clocked,
but I don't think I have enough info for that either. All of the
printed documentation for this system is gone, Does anyone happen to
have a manual or detailed specs in PDF form?

Any help would be appreciated... Thanks.

BTW, I'm running Ubuntu on it, and it works surprisingly well. But
some operations are obviously CPU-bound and really drag. Having
increased the memory to 192M has no doubt helped immensely.