Dually p2 help

ok i just recently "borrowed" an old dual p2 dell server from my job problem is it only had 1 450 p2 chip in it, but i recently aquired an old compaq that has a p2 350 in it....i wanna pick up a dual p2 mobo (the server one uses scsi so i cannot u use it) and run a dual p2 rig for folding...but since the chips are different speeds i know it wont work, is there a way for me to underclock the 450 to 350 or vice versa so they are equal...if so...what mobo should i get??

Thanks guys
Fed