I wouldn't post here, this is a forum dedicated to keeping PowerPC Macs (with their original innards and architecture) alive. There are plenty of other forums dedicated to making a hackintosh out of a G5 case.
If the 2.7 Ghz PowerMac G5 works I recommend keeping it or selling it and not gutting it... 2.7Ghz G5s are rarer then most and it would be a shame to gut a working one. My Dual 2.7 runs nicely