I know it can be done, because someone already did it ( upgrade the 68040 with an 68060 ). I don't remember who did it. But the guy got some information from Phase5. It was in those day when it was so popular to tweak your accellerator until you started sweat! ;-)
By the way, I got my 68040 removed and had a soket placed on the BlizzardPPC. Some guy I Norway (Bergen) fixed it for me...
I'm wondering... Does anyone know if there was a problem with the software on the BlizzPPC that had to overcome?
I think the Mhz of the crystal controlling the 68k, also controlls the SCSI II controller, which gave you a problem when increasing the frequenzy... whatever... If you want it done right, don't listen to me. I forgotten to much ;-)