I went looking for a Motorola 68040 running at 40Mhz on ebay, but was unable to find one. But reading Chris's FAQ, he mentioned that with a little machining, a heat sync and fan made for a Intel 486 processor would almost fit the Motorola 68040. So looking around on ebay, I found what I liked, but it was sure costly. I ended up with this guy:
http://www.ebay.com/itm/321746137982?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I use my dremel tool often, so I suspect I can make that puppy fit.
I will keep searching for a 40Mhz 68040.
jack the new kid.