I did this way back in the day and it's barely noticeable.
It's a fun little hack to learn something with, but that's about it.
ur 56Mhz 060 spoiled u

Did u do the hack by itself? Or did u also add a 68010?
The hack by itself would be just about nothing... but if u have a 14.3 Mhz 68010 then LOOP MODE would be really fast. If you happened to be running a piece of software that happened to make use of LOOP MODE in a critical piece of code then it could be very noticeable.
But the worst 68030 is still massively faster. And a 68060 is massively faster than a 68030. But in 1985/86 this hack could have been interesting.