[Jack21]

First, to answer your question, there are two current sources for aluminum Cleveland heads. FMS sells the Yates heads, and Blue Thunder has recently introduced aluminum Cleveland heads. Some of the Ford hipo shops are now carrying them.

They're relatively expensive (~$1,800 US), and not particularly necessary on a Cleveland engine. There was a time when you almost couldn't give a set of Cleveland 4v heads away because 351 cubes was too small of an engine to use the airflow of the stock head.

Putting a set of these Blue Thunder Clevelands on a stroker 393 - 427 Windsor that can use the airflow might be worth looking into.