That's not the case though. We had the various 060 boards for the Amiga. My PP040-33 smoked all of them in Speedometer testing. It is also faster than the 840AV's benchmarks, even though it is a slower speed CPU. Norton's test is not very thorough, and certainly does not represent all of the various math tests that typical benchmark programs should perform. Snooper, Speedometer, and several others were commonly used for comparison (never Nortons), but Speedometer 4.0 was the defacto standard for benchmark testing.
The Mac OS does cache clearing everywhere, especially in system traps, and clearing caches on an 060 takes far longer than an 040 so there is a big speed penalty from that. I got tired of typing CacheClearU().
I am still very convinced that a good FPGA 040 core is the way to go for compatibility and speed. I created a complete 68040 emulation (CPU, FPU, MMU) for FUSION-PC, my PC version of FUSION. So, I have all of the simulated microcode necessary for a conversion to FPGA. The FPU would have to be created from scratch as I used the x86's FPU in FUSION-PC, but the MMU was part of the software CPU core. I know microcode well, PALs, GALS, PEELs, etc. but unfortunately, I don't know VHDL or Verilog well enough currently to tackle such a project. I am going to take some time to learn the ins and outs completely and see if I can do a full conversion.