I would have to agree with Castellen about this.
Desoldering the 68060 CPU is a big task with such a rare and expensive PCB, even for experienced technicians. And there is the risk of accidentally damaging the circuit board. True, with hot air you can loosen any 'sticky' pins after desoldering all of them just before dropping the CPU out of the PCB, which is the way to do it of course, but still you are taking a risk doing this since a lot of heat is required to raise all the pins to a high enough temperature.
I replaced the -socketed- 68040 on my Blizzard 2040 with a rev. 6 68060 including the required modifications and found that it still needs some slight cooling air across the bare chip or a passive heatsink to keep it running as cool as you read about this rev. 6 version. Without any air displacement the bare CPU still does get a bit too warm to leave it like that for my feeling.
Of course, had it been a soldered 68040, I would still have desoldered it to gain the speed advantage, however if it already was a 68060, I would have felt it's not worth it. I would have made sure it was sufficiently cooled to keep it at the same cool temp as the rev 6 one is.
