unlike the 400Mhz Sawtooths, G4 350MHz G4's have no hope of using Dual processors as they were pre-Rev 7 boards (Uni-north 3 instead of Uni-north Rev 7). you need Uni-North 7 in order to drop a dually in it.

I got my Sawtooth 400Mhz from Dan, and quickly dropped a dual 450Mhz G4 module in it and it's now running with that. With help from another forum member, I will be upgrading from 512MB RAM to 768MB

I just loaded Leopard on it too. it's VERY snappy