Processor upgrade options...

I asked this question a while back but since I didn't get an answer I am asking it again. I have an HP 4445 with a PPGA Celeron 366 processor and the i440ZX-66 chip-set. I am wanting to install a new Celeron but am fuzzy on which one I could acutall install. My motherboard has no jumpers, even though it is not a "jumperless" motherboard. Basically the motherboard has been locked in place with a 66mhz bus. I can't change any of this but I think that I could install a new, faster Celeron. I was thinking about a 633 but this is an FC-PGA processor. I am wondering if this will work in my system, it is basically the same thing just a faster clock. I also know that at the 600 mark, Intel started using the coppermine core so is this going to make a difference? If anyone can help please let me know.