I also bought a 040-060 adapter and put a 68060 rev1 with full FPU and MMU and the updated Kickstart ROM with the patched Exec.library.
It works fine, but it is much slower, because the 3640 card doesn't have local memory. Without it will be slow.
The performance is between a 040/40 MHz and 060/50 MHz.
I'm using a 50 MHz crystal.
