[Rick Parker]

I think Bernie already has this engine done and in a car? 8.2 Aluminum block (RDI?) with Yates heads AND Webers on a fabricated manifold, and yes it makes big power. It has been fully detailed here previously. As far as the quality and intended market of various blocks is concerned, the Boss block was developed by Ford to keep them in the game that they invented. Their stock of 5.0 blocks is probably severely dwindled and the Boss block appears to play well on a known name by immediately being identified with the Boss 302 Mustang, and fills a need between a basic block and an all out race piece. The intended market would thus be considerably larger than one for an all out race engine.
The Man-O-War block is indeed a very well designed item intended for huge power levels, anything below those are not begining to tax it's ability whatsover. It offers huge "Insurance" for the above average street or open track type engine. The designed ability to use 5 studs/bolts per cylinder increases it's appeal to the superchaged and spray crowd in Drag Race Mustang applications but the head choice is obviously limited at this time, but will surely be addressed by other manufactures as demand warrants.
It's no secret that the 5.0 Mustang was the "Torch Carrier" for Ford that led to all the development of parts for the 289/302 of which many could be ultimately utilized on the 351W. But there was a time not too long ago when the 351W didn't receive a second thought. It was essentially strangled with cylinder heads with port sizes designed for and engine with 130 fewer cubic inches (221). It was just there to fill the need for an engine to compete with the 350 in GM's lineup without any thought of a performance varient. The Cleveland was thought to have more potential, and so hot rodding efforts were directed towards it, for a few short years.
With the advent of 5.0 Fox Bodied Mustang and its underhood dimensions, coupled with impending EPA restrictions, Ford was able to get more continued bang for the buck from the inline valve headed 302.