Hello,

Here is my powermacs motherboard/chassis experience:

5500 <==> 5400 OK

5300 <==> 5200 OK

5200/5300 <==> 5400/5500 Fits but doesn't work

(note: theses experiences did not damage any hardware)

LC630 is a 68K mac, I don't think putting a 5400 motherboard in it will work.