@voytech
I have read that genuine 66MHz rated 68060s can be overclocked to 75MHz provided you install some serious cooling.
However, I dont think the 14% increase from 66MHz to 75MHz is worth the risk of killing what is a difficult (and expensive) to replace part.
Another point to note about 68EC060s - most software that is written to take advantage of the 68060 tends to assume that its a full 060.
I have heard of lots of 060 apps failing to work on EC060 thus forcing the use of 020/030 code. Naturally it runs very quickly, but 68060 optimised code on an 060 can be considerably quicker than 020/030 code on an 060 due to pipeline optimisations etc.
Given the choice, I'd go for a full 68060 @ 66MHz than a 68EC060 @ 75MHz any day...
