Ron Earp: "For production cars, but Ford used the engines in the '90s for the V6 Cup series. Technically Ford used an SVO block for this that was beefed up, but more than a few folks have built clones of the engines using the standard 3.8L block & boring/stroking these to 4.5L. All the SVO parts work on a 3.8L block."

Interesting. As I have never taken an interest in the Ford I6/V6 until this IT project, that engine never crossed my radar. I went back thru my old Ford Performance catalogs & TAH DA!!! ... there it was. Thank you for the info. Those heads should help improve my F/R weight issue also.