Windsor and Cleveland heads are interchangable with water jacket modifications, but from a bolt on standpoint, a windsor with a set of Yates heads will blow a cleveland so far into the weeds, you'd need the hubble telescope to even get a clue as to where it went.
Pound for pound the windsor engine (thanks to the good ol 5.OH!) has so much more potential nowa'days. it's ligher, smaller and less costly to modify. Not to mention most of the stuff out for it is lightyears ahead in technology compared to the cleveland stuff. As far as port flow and the like, I guess the 4V heads do flow good. They have enough volume to ventilate a freak'n mine shaft without weezing. Now if you add things in like velocity, swirl, etc. those big numbers don't add up to squat. Especially if it's all lazy airflow. I know there are more than a few cleveland diehards here
, but the clevland is to the windsor what the windsor is to the modular motor.