> Amiga turbo boards won't help at this point. They are tailored
> for the respective Amiga model, have a lot of glue electronics around the CPU
> and usually do not plug into the original CPU socket but into some special
> expansion socket/port.
> Additionally, for the 040/060 chips you might need extra software
> to catch the instructions not available / differently behaving on
> 040/060 vs 030.
For Mac this is possible at least for a 68040 in most major 030 systems.
You can go up to 68040/45 (Sonnet), and I believe a rarer card even goes
to 68040 /50. 68060 is not possible afaik.
These are all special accelerators for (afaik mainly newer) Mac II based
systems, and (and this is the bad point), often they need OS support,
specially if it is not merely a faster version of the same processor. (so
like a 040 in a 030), and to enable the (added) L2 cache which is usually
also on that accelerator board, since the avg II comes without.
MacOS drivers are usually provided, but if you run some free unix on your
ancient Mac it is hard. (though some are supported by NetBSD, specially