The 040-060 adapters have worked well for me, I have 3 of them.
In order to use one in a 3000 it needs to be very low profile so it will fit under the disk drive shelf, and there is no room for a heatsink or fan unless a hole/slot has been cut into the metalwork - this is the case with my aa3000+ (by the case’s previous owner) so I can have a fan. An 060 @50mhz is generally fine without cooling though.
With cooling an 060 on a WarEngine is great - the one in my A4000 is running at 96mhz. The WarpEngine has a fast memory controller too compared to many other accelerators. Oh, and the scsi still works because the board/cpu clock is separate from the scsi clock
