That would explain a few things.....and I also heard that the 400's were dropped due to space limitation reasons, I have had ideas for a few years now to install a 400 or 460 into a late-80's crown vic wagon, and for all of the size of the hood, there really is not much room under there for anything much larger than a 302 without bumping into something else. The SIX explanation sounds great, it is hard to continually detune an engine with huge intake and exhaust ports, that is easily done with the tiny heads of the windsor line. Hey, now I am rambling.....